Recently, bed bugs appeared in my apartment.

Bed bugs (Cimex lectularius) are indoor pests belonging to the genus Cimex in the family Cordycepsidae, order Hemiptera. In Japan, they were once nearly extinct after World War II due to the widespread use of effective insecticides, but have begun to increase again since around 2000 due to the ban on the use of DDT and the increase in inbound tourism (Hirao, 2010).

I never imagined that I, someone who works with insects, would be bitten by bed bugs. In a way, it was fortunate that I was able to take many photos of bed bugs (?), but I was bitten 6 to 10 times every night on the backs of my hands, arms, and neck, and on top of that, I became ill and caught a cold, so it was a very painful experience.

Therefore, here I would like to summarize the ecology of bed bugs, along with my personal experience from their initial infestation to eradication, and refer to relevant literature.

In conclusion, there are limits to what you can do to get rid of them yourself, and if you want a quick solution, I think it's best to rely on a pest control company. Even I, who loves cleaning and lives a semi-minimalist lifestyle, felt that way, so I think there are probably no exceptions.

The reason is that while laundry and commercially available insecticides (excluding pyrethroids) are effective, liquid sprays or gaseous fumigations do not spread sufficiently throughout a real house with a lot of clutter, and since insecticides are ineffective against eggs, continuous pest control is necessary after hatching.

Depending on the company, many also use other methods such as high or low temperature insecticide application, sealing gaps, trapping, and visual inspection, resulting in a completely different level of service.

Contrary to what is advertised, the extermination costs are typically over 100,000 yen, which is quite expensive. However, considering the certainty and time saved, I believe it's well worth the payment.

I think self-extermination is only feasible for those who are prepared to fight for a long time.

This article summarizes a real-life experience review of bed bugs, from their discovery to eradication, along with information about their ecology.

The first sign of trouble: From bite marks and symptoms to realizing "it might be bed bugs."

The first physical abnormality I noticed

The first symptoms of bed bugs appeared in mid-April. After visiting a friend's house with a large group of people, I developed slightly itchy red spots around my wrists, and at first I thought it might be due to a viral cold. I had previously developed similar spots from a viral cold, and I actually developed chills and caught a cold afterward, so I was convinced that "this must be a cold caused by being with other people."

This cold lingered for quite a while, with persistent runny nose, cough, and sneezing, and even a loss of taste. Although tests showed it wasn't coronavirus or influenza, it worsened to the point where I developed cough-variant asthma even after recovering.

After recovering from my cold, my health improved somewhat, except for my cough-variant asthma. However, for some reason, the spots on my skin continued to increase rather than subside.

It was at this point that I finally started to think, "Could this possibly be caused by an insect rather than a cold...?"

This was because I had prior knowledge of the issue. During my graduate studies, I heard through someone that there was a lot of talk at the public health center about the increase in bed bugs, and I did some research on it myself.

Just in case, I lifted the mattress I always use and examined the mesh part, and found something very small wriggling. I picked it up with my usual tweezers and examined it with a stereomicroscope... and there it was. It was a bed bug.

I found it and even took a picture so easily, but in reality, it's not that simple.

The media often focuses on the adult form, which is large, brown, and relatively conspicuous. However, the first-instar larva, newly hatched from the egg, is only about 1.5 mm long, and only those with very keen eyesight can spot it against a white background. Most people would simply overlook it.

Even more cleverly, and this is a common characteristic among insects, bed bugs will stop moving when they sense they've been detected by vibrations or other means. Mammals, including humans, find it extremely difficult to spot stationary objects.

Furthermore, since most people don't have tweezers or a stereomicroscope, they probably wouldn't be able to catch a first-instar larva and definitively identify it as a bed bug.

In that respect, I think we were quite fortunate to have discovered it so early.

Most people would be wise to be suspicious based on the symptoms of bite marks.

Characteristics of bite marks and differences from tick bites

In the case of bed bugs, they primarily target the arms, legs, and neck, and unlike fleas, lice, mosquitoes, and ticks, the red bite spots often appear in a straight or zigzag pattern with 3 to 5 spots close together (Akhoundi et al., 2023). This pattern is sometimes called "breakfast, lunch, and dinner." However, since bed bugs are only active at night, this is merely a symbolic name.

There are various theories as to why this pattern occurs, so I will omit them here. For more details, please refer to Doggett et al. (2012).

The spots may become raised or turn into blisters, and the itchiness varies depending on the stage of larval development and individual differences, ranging from an itch as mild as a mosquito bite to an itchiness so severe that you can't help but scratch.

Because I was sleeping in long sleeves and long pants at the time, the area I was bitten in was limited, mainly the back of my hands, wrists, and the front of my neck. If you notice that exposed areas are being bitten regularly every morning, you can strongly suspect bed bugs. However, in my case, even though I was wearing long sleeves, they often managed to burrow into my forearms and up to my elbows and bite me.

Unfortunately, bed bugs are nocturnal and inject an anesthetic when they bite, like mosquitoes, so you rarely notice you've been bitten, and by morning they've hidden away in the shade, leaving almost no trace (Akhoundi et al., 2023).

Humans toss and turn in their sleep at night, and it seems like they could be crushed at any moment, but normally you never see bed bugs being crushed.

This is likely due to their high speed of movement and their extremely flattened shape. As someone who studied biology, I was impressed in a way, thinking, "Evolution is amazing!", but it can also be said that they have some troublesome characteristics.

The bite itself usually heals naturally within one to two weeks without treatment, so there is no need to worry (Akhoundi et al., 2023). There is currently no evidence that they transmit dangerous infections like mosquitoes.

Being bitten is very stressful, but try to stay calm, wash the bite with soap and water, and apply a topical steroid or antihistamine (Akhoundi et al., 2023). Scratching is the worst thing you can do. I didn't have a severe case, so I managed without medication. In Japan, I think it would be something like Lindelon Vs ointment or Muhi.

Ideally, I would recommend going to a hospital for an examination, but even then, there's no guarantee that there will be a doctor who is knowledgeable about bed bugs (Doggett et al., 2012). Ultimately, even if you decide to call a pest control company, you'll need to collect actual insects or take photographs as evidence. If you're unsure, I think it's more reliable to have a pest control company examine it directly rather than going to a hospital.

Where are they hiding in your house? A complete guide to finding bed bugs in your home.

Whether you're trying to get rid of bed bugs yourself or hiring someone to do it, the first step is to find out where the bed bugs are hiding during the day.

Hiding places indicated in the literature

Bed bugs tend to spread mainly in bedrooms because they feed on blood at night.

Studies have shown that within bedrooms, the incubation rates are 85% in beds, 52% in bedding, 37% in baseboards and carpets, 26% in furniture such as lamps and dressing tables, 25% in sofas and chairs, 14% in walls and ceilings, and 6% in clothing (Hirao, 2010).

In severe cases, they may enter electrical outlets, pipes, and air ducts, but this is rare (Delaunay, 2012). While there is a small possibility they could enter electrical appliances, this is usually uncommon and therefore a low priority.

Hiding places that were actually confirmed at home

Ultimately, what I was able to confirm with my own eyes was the inside of the mesh of the folding mattress, the top and middle of the curtain, the corner of the flooring between the mattress and the curtain, and the inside of the bench stool next to the mattress.

In other words, it was only found around the bed, and conversely, I didn't see it around the desk, kitchen, bathroom, or toilet. If I had left it as it was, it would have likely spread to other rooms.

Regarding bathrooms and shower rooms, bed bugs are vulnerable to water and have difficulty climbing on the smooth surfaces, making them less likely to enter (Delaunay, 2012).

First, I think it's best to thoroughly search around your bedding. The larvae are a yellowish-white color, and the adults are brown, so they can be difficult to spot depending on the background color, and the first-instar larvae are very small. Shining your phone's flashlight on them will make them easier to find.

Another sign is what's called bloody feces, which, horribly, can be found in the corners of a room, consisting of feces mixed with your digested blood. Check for this as well.

Bed bugs are related to stink bugs, and when they attack, they emit a sour odor. In severe cases, this odor may linger strongly (Delaunay, 2012).

First aid measures taken: Washing, drying, and cleaning

If you discover bed bugs, the first thing to do as emergency measures is to thoroughly wash, dry, and clean your home. This method has been noted in literature (Hirao, 2010). However, don't expect this to completely eliminate them.

The effects of washing and drying

Regarding washing, it has been confirmed that all adults, larvae, and eggs are killed by washing in 60°C water and tumble drying at 40°C or higher for at least 30 minutes, or by dry cleaning (Hirao, 2010).

This can be done in a home washing machine with a drum-type dryer or at a laundromat. While there is insufficient evidence for using only a dryer, bed bug exterminators recommended running it on a high setting for 40 minutes.

It is said that even regular room-temperature washing is effective against everything except the eggs, and when I washed curtains that couldn't be put in the dryer, I found the dried-up corpses of large bed bugs.

Vacuuming and sun drying in practice

Vacuuming is effective in reducing the number of bed bugs, as it not only sucks them up but also physically kills them with the force of the suction.

It has been confirmed that 97.4% of adult insects die within a week, and the remaining insects all die within eight days. It is also known that 100% of larvae die within one day (Tanaka & Tanaka, 2017).

However, since I only had a Swiffer-type mop, I couldn't expect this effect. I could see with the naked eye that the Swiffer-type mop was wiping away the larvae, but I think it's inferior to suction.

Sun-drying is also effective; it has been found that wrapping them in a black plastic bag and turning them over so that both sides are exposed to the sun can kill insects by reaching temperatures above 80°C, although this is quite a time-consuming process.

Attempting to exterminate pests yourself: The effectiveness and limitations of insecticide sprays.

However, simply washing, drying, and cleaning has its limits. In fact, it didn't make them go away.

So, although I was hesitant to use it if possible, I decided to try it out and used insecticide.

Ingredients and effects of commercially available insecticides

There are four types of active ingredients in commercially available insecticides used for bed bugs: pyrethroids, organophosphates, carbamates, and metadiamides (brofranilide).

However, even if major pyrethroid-based insecticides are labeled "effective against bed bugs!", they have little effect on bed bugs today. Specifically, this includes products like LEC's "Balsan One Touch Smoke Type" and Earth Pharmaceutical's "Medicinal Bed Bug Cockroach Earth."

The bed bugs that have reinvaded Japan have developed resistance to pyrethroid insecticides and are a population known as "super bed bugs." It's like a monstrous evolution, reminiscent of Doma from Demon Slayer, but such evolution actually occurs in many insects. It's an ability gained through the sacrifice of countless corpses, and is the result of natural selection (or artificial selection).

Actual experiments have shown that pyrethroid-based fumigants have a mortality rate of less than 30% even after 72 hours, and spray formulations have a mortality rate of less than 60% (Kurashima, 2024).

Organophosphates and carbamates have traditionally been effective, with a 100% eradication rate reported after three weeks (Muto, 2015).

However, bed bugs that have developed resistance to organophosphate and carbamate insecticides have now been identified both domestically and internationally, and it has been pointed out that these insecticides may become ineffective in the future (Suga, 2022). They may still be effective in 2026, but their effectiveness may decrease year by year.

Broflanilide is a new drug and can be used without problems for the time being. One study showed an eradication rate of 95% or higher after two weeks (Kurashima, 2024).

Therefore, always check the active ingredients on the label before purchasing insecticide. Many people are buying pyrethroid-based insecticides and suffering because they are ineffective.

The product I used this time was Earth Pharmaceutical's "Zerono Night Cockroach and Bed Bug Spray, 1-Push Type, 60 Uses".

This product contains broflanilide (brand name: Tenevenal) as its active ingredient.

I used this product for about a week, spraying three times into the air daily and three times on the areas where I had previously found bed bugs. The manufacturer recommends using less, so please proceed at your own risk.

As a result, I started seeing about 3 to 5 bed bugs in a near-death state every day. I think it played a role in steadily reducing their numbers.

While cleaning further, I discovered an adult insect in a near-death state, which is likely the parent of all the larvae that had entered the room!

While cleaning, I found several first-instar larvae on the quick wiper. Since wiping will wipe away the insecticide, be sure to spray it again after cleaning.

Other options include LEC's "Balsan Ambush Spray" (carbamate-based) and Earth Pharmaceutical's "Zerononight G Cockroach and Bed Bug Fumigation Agent for 6-8 Tatami Mats" (broflanilide). I haven't tried these myself, so they might be better depending on the situation.

Precautions when using insecticides

However, these drugs are not without risk to humans. Although it is unlikely to be these drugs, there have been deaths from bed bug pesticides overseas (Laborde-Castérot et al., 2024), and while these drugs are currently used after testing and deemed safe, there is no knowledge of long-term exposure, and the future is uncertain.

The insecticide DDT was once considered harmless and was misused as a "miracle drug." Bed bugs also saw a decline in numbers due to DDT (Akhoundi et al., 2023), and were nearly extinct in Japan. However, DDT has now been confirmed to be carcinogenic and is no longer used except in a very limited number of regions (Le Couteur & Burreson, 2003).

Remember that no medicine is completely harmless, and use it in moderation.

But it still doesn't go away... The recurrence revealed the "pitfalls of amateur pest control."

I combined several possible control methods, but to put it simply, I couldn't eradicate them on my own in about two weeks. Even after using insecticides, I continued to get bitten in multiple places every day.

There could be several possible causes.

The problem recurs after evacuating to a different location.

First, while washing and drying clothes and cleaning can reduce their numbers, if these aren't done simultaneously, bed bugs that have fled to another location will return to the same spot.

I actually washed my curtains and sheer curtains once, but after a while I started seeing bed bugs on them again. I couldn't dry them at a high temperature, so it's possible that eggs remained.

It's possible to get it to last if you wash it many times, but it requires a lot of patience.

Furthermore, there are parts that are impossible to wash, dry, or clean, no matter how hard you try, such as the inside of a mattress or an air conditioner. If they take refuge in those areas, there's nothing we can do.

Prolonged duration due to house structure and mass egg-laying

Regarding insecticides, the aforementioned claim of 100% eradication is merely the result of experiments. In reality, houses have complex layouts, and with a lot of furniture and other items, there are many gaps through which insects can enter, so they may not penetrate rooms so easily.

Furthermore, since people typically clean their homes frequently, the chemicals are wiped away. In fact, there is even a theory that the chemicals might be more effective in a dirty room (Kurashima, 2024).

Furthermore, the concentration of commercially available medications may be too low.

More importantly, these insecticides, which act on the insect nervous system, have virtually no effect on eggs that are immobile and protected by their shells. Experiments have shown that even when various insecticides are sprayed directly on the eggs, the survival rate exceeds 80% (Hinson et al., 2016).

Furthermore, a female bed bug lays an average of 131.9 to 155.7 eggs in her lifetime (Polanco et al., 2011c). Another study suggests 200 to 500 eggs (Akhoundi et al., 2023). She doesn't lay all of these eggs at once, but rather a few at a time after each blood-feeding, laying about five eggs per day.

Therefore, if, like me, the adult insects lay eggs in your room, even if the medication is effective against the hatched individuals, a long battle is inevitable.

I learned about professional pest control methods and typical costs by consulting with a pest control company.

Based on these results, I decided to hire a pest control company (extermination service).

The reason I decided to hire a professional was that, although the insecticide spray was effective, I felt it would prevent the situation from escalating and that I couldn't be sure it would completely eradicate the problem.

But the biggest deciding factor was when my parents told me, "We have pets, so please don't come back home until the bed bugs are gone" (laughs).

Bed bugs also opportunistically feed on the blood of pets. In other words, although it is not their primary food source like human blood, there is clear evidence that they feed on the blood of dogs, cats, rabbits, and birds such as chickens when the opportunity arises (Black et al., 2021).

I was originally supposed to attend a memorial service at my parents' house, but I couldn't go because of bed bugs. When I think about the risk of spreading bed bugs to other people and causing them trouble in the future, I think it was the right decision to hire a professional exterminator.

Costs and scope of work revealed in the estimate

I think it's best to get quotes from several companies. I requested quotes from two companies, a large corporation and a small to medium-sized enterprise.

While the large company responded quickly to my email, they provided an estimate without actually coming to my house to inspect the condition. In contrast, the small company came to my house the same day, inspected the condition, and prepared an estimate. As a result, although the small company's initial estimate was higher, I decided to go with them.

I want to believe that bed bug extermination is unlikely to be a complete failure, but I think it's worth considering not only the price, but also whether they are quick to act rather than just talk, whether they can actually find first-instar larvae in your home, and whether they advertise themselves as being good at bed bug extermination as well as general pest control.

While some companies advertise prices online as starting from 40,000 yen for a single-person apartment, you will almost certainly not get paid that price.

This is because a second extermination is almost certainly carried out two weeks after the first. This is a standard extermination method because, as mentioned above, the pesticide is ineffective while the eggs are still in the egg stage, so treatment is necessary after the eggs have hatched (Campbell & Miller, 2017). It takes 4 to 12 days for the eggs to hatch (Akhoundi et al., 2023). You should be wary of any company that doesn't follow this procedure.

It might seem like a gray-area advertisement that misleads customers, but even ordinary businesses do this (probably due to price competition), so it's probably best not to judge a business's quality based solely on its price.

I ultimately paid around 140,000 yen for the extermination, including the guarantee, but if you live alone, the price might be a bit lower. However, I compromised because I wanted it done quickly. In any case, I think it's guaranteed to cost over 100,000 yen.

Differences in pest control methods among different companies

Pest control methods vary from company to company. Some use only chemicals, while others combine various methods. If a company offers a guarantee period, any choice should be fine, but if you are hesitant about the use of chemicals, a company that advertises using minimal chemicals might be a better option.

The following are typical pest control methods used by pest control companies.

• Heat treatment: Kill insects with high-temperature steam.
• Cooling treatment: Kill insects with dry ice or similar methods.
• Vacuum treatment: Use a powerful vacuum cleaner to suck up the bed bugs.
• Chemical treatment: Applying chemicals. This often involves not only fumigation or spraying, but also applying liquids to the corners of the room.
• Sealing treatment: Seal small gaps in the corners of the room with a hardening resin.
• Capture and treatment: Place bed bug traps (bed bug traps) in the corners of the room to directly capture and kill them and prevent re-infestation.

Warranty periods vary from company to company, but they are often 3 months, 6 months, or 1 year from the second application.

Considering the life cycle of bed bugs, it takes 4 to 12 days for eggs to hatch (Akhoundi et al., 2023), and about 1.2 to 1.3 months for them to develop from egg to adult (Polanco et al., 2011a). Their life cycle is 2 months (Izri et al., 2020), so theoretically, 3 months might be sufficient.

However, there's always a possibility that they could be brought in from outside, or hidden in household items and accidentally emerge, stinging you again a few months later, so six months might be a safer timeframe.

Bed bugs are often said to be able to survive for over a year without feeding on blood on the internet, but one study showed that first-instar larvae live for an average of 13.8–36.3 days, and fifth-instar larvae and adults live for an average of 41.5–142.6 days, suggesting that this claim might be an exaggeration (Polanco et al., 2011b). Another study yielded similar results (Akhoundi et al., 2023).

If we take these numbers at face value, it seems unlikely that it will appear for at least six months.

The process leading up to the day of the pest control service and the number of days it took for complete eradication.

I think they can start the work within a few days. In my case, they inspected the site on the same day as my initial contact, and performed the first extermination five days later. I scheduled the second extermination two weeks later. So, it took 19 days from the initial contact to complete extermination, but I stopped getting bitten six days after the first extermination.

Preparation before construction

There may be things you need to do yourself before the day the contractor arrives.

In a common scenario, household items, excluding large furniture and appliances, must be bagged. This is to isolate bed bugs from the room. Bed bugs are thought to be unable to climb smooth plastic bags.

However, bed bugs are said to be able to break through thin plastic and get out, so you will need thick 30L or 45L transparent plastic bags that are at least 0.04mm thick. This task is quite difficult; it's almost like moving house.

These plastic bags aren't usually found in regular supermarkets, but you might be able to buy them at home improvement stores. I bought a pack of 30 45L transparent heavy-duty garbage bags (0.05mm thick) at Kohnan, but if you're willing to pay an extra fee, the service provider can provide them, so that's fine if you don't want to think about it too much. Some service providers might even include them in their plans from the start.

These bags cannot be returned until the second treatment, two weeks later, completes the extermination process. Therefore, be prepared to live with the bags for at least two weeks.

Furthermore, customers were encouraged to use coin laundries or dry cleaning services for clothing that can be washed and dried.

From here on, the methods used by the company I hired may differ depending on the company.

Details of the first and second construction phases

For the first treatment, the person in charge went out, and the aforementioned chemicals were applied and sprayed throughout the room, and gaps were sealed. I was told it would take about half a day, but in my case, since the room was small, it was finished in about 3 hours. That's the speed of a professional!

Backpacks and bags used when going out are also subject to pest control, but these were visually inspected and treated with insecticide. Bags containing frequently used items were also treated with insecticide at that time.

On the first night after the treatment, I felt like I was still being bitten in a few places, but when I returned home the following evening, I found three dead insects. I think the insecticide applied to the corners of the room had worked. I haven't been bitten since then.

For the second treatment, if bed bugs remain in the room, the work will be performed in the same room as the first treatment, but the bags will also be checked to ensure that no bed bugs remain.

I haven't had the second treatment done yet, so I'll report back once it's completed.

Measures to prevent recurrence and ensure it never happens again

Possible entry points

I still don't fully understand why bed bugs have appeared in my house.

Since bed bugs do not reproduce asexually, they must mate, making it unlikely that a single larva would enter a house and reproduce. The most likely scenario is that a mated adult bed bug entered the house.

I've only been able to find one female adult at home, so this is the pattern I'm considering for now. I started experiencing stinging symptoms around May, but the exterminator suggested that the insects probably entered the house around December.

However, there are many possible entry points, and we are unable to pinpoint a specific one.

Generally, outbreaks have been reported in all forms of accommodation and transportation, including hotels, trains, airplanes, and ships (Delaunay, 2012).

In my case, there are two possible scenarios.

One possibility is that I brought bed bugs back with me from my travel destination. I'm quite comfortable in small spaces, so I often use capsule hotels when traveling alone. However, there are many international tourists due to the inbound tourism trend, and I was careless, so adult bed bugs may have gotten into my backpack or jacket. I was staying at a capsule hotel in Tokyo around January. Checking the 'Bed Bugs Map Japan', it seems that there was a bed bug infestation there about two years ago.

Another possibility is that they got mixed in with a package. Because of my job, I have specimen samples sent to my home in cardboard boxes, and I also frequently make purchases online from Amazon and other retailers, so it's possible that adult bed bugs got mixed in with one of those packages.

Hotel and luggage measures

Are there any preventative measures that individuals can take? Regarding hotels, the following methods have been suggested in research (Delaunay, 2012; Hentley, et al., 2017).

• Upon arrival, use a flashlight to quickly check the bedding area, and if you find any suspicious signs, do not use that room.
  • Check the seams and piping of the mattress.
  • Check the corners of the bed frame.
  • Check the top of the curtain.
  • Check the gaps between pillows and sofas.
  • Black spots (blood and feces), bloodstains, eggs, and larvae were observed.
  • Since bed bugs are related to stink bugs, they emit a sour smell, so check for a strong odor.
• Place your belongings away from the bed (such as in the bathroom). Bed bugs are less likely to enter bathrooms and shower rooms because they are slippery, difficult to climb, and are vulnerable to water. If there are no other options, place them on a chair or similar object in the center of the room, away from the walls.
• Seal your belongings in a large plastic bag. Smooth plastic bags make it difficult for bed bugs to climb.
• For exposed skin, use mosquito repellent spray containing DEET. In Japan, examples include Earth Pharmaceutical's "Saratect."
• Sleep with clothes on. You're less likely to get bitten through fabric.
• Store your pajamas in a separate plastic bag.
• Don't leave worn clothes lying around. Experiments have shown that soiled clothing absorbs human odors, attracting bed bugs and providing them with a "foothold" for movement. Put clothes you've taken off into a plastic bag immediately.
• Upon returning home, immediately do the laundry, and wash or dry any suspected clothing at a high temperature. As mentioned above, this will kill the insects, including the eggs.
• Don't bring your suitcase straight into the house. Wash it in the bathroom if possible.

Another option is to avoid hotels that have a history of bed bug infestations. 'Bed Bugs Map Japan' compiles evidence-based bed bug sighting records on Google Maps (Bed Bugs Map Japan, 2026). While this may be helpful, along with the hotel's attitude towards bed bugs, it should only be used as a reference; there's still a good chance bed bugs could be found in hotels not listed.

However, even considering all of the above, I think it's difficult to implement a perfect intrusion prevention measure. While some hotels will properly exterminate the pests, there are also cases where they turn a blind eye, so a societal approach may be necessary.

The current price range for bed bug extermination makes it difficult for low-income individuals to afford it, which could lead to the spread of the infestation.

Once they get into your house, cleaning alone won't prevent them from breeding. I have very few possessions and I clean fairly often because I like it, but they still breed in my house.

Summary: Early detection and correct diagnosis are key when it comes to bed bugs.

Naturally, bed bugs grow the more blood they suck.

If left unattended, a single female can lay approximately 5 eggs per day, averaging 131.9 to 155.7 eggs in a room, and if it's in your own private room, these offspring will be raised solely on your blood.

These insects will never disappear even if left unchecked; in fact, they can even inbreed, allowing the next generation to grow (Fountain et al., 2014). Studies have shown that colonies can be founded by a single adult female, and that their genetic diversity is extremely low.

If there is no pest control and the population has a normal food supply, the number of eggs and larvae will increase exponentially. Even under the harsh assumption of starvation where females do not lay eggs daily, simulations show that the population doubles every 13 days (Polanco et al., 2011a).

At first, you might dismiss it as something like a mosquito bite, but once they grow into adults, their numbers multiply exponentially (like rats), and it becomes impossible to control.

Let's take some measures before that happens.

The best option is to hire a reputable pest control company, but if that's not possible, be sure to use multiple methods, such as washing and drying clothes, using a vacuum cleaner, and using insecticides other than pyrethroids.

I hope this article will be of some help to those suffering from bed bug infestations.

References

Akhoundi, M., Zumelzu, C., Sereno, D., Marteau, A., Brun, S., Jan, J., & Izri, A. (2023). Bed bugs (Hemiptera, Cimicidae): a global challenge for public health and control management. Diagnostics, 13 (13), 2281. https://doi.org/10.3390/diagnostics13132281

Bed Bugs Map Japan. (2026, May 17). Bed Bugs Map Japan. https://bedbugsmapjapan.com/

Black, MK, Chandler, JG, Trout Fryxell, RT, & Vail, KM (2021). The Common Bed Bug (Hemiptera: Cimicidae) Does Not Commonly Use Canines and Felines as a Host in Low-Income, High-Rise Apartments. Journal of Medical Entomology, 58 (6), 2040-2046. https://doi.org/10.1093/jme/tjab070

Campbell, BE, & Miller, DM (2017). A method for evaluating insecticide efficacy against bed bug, Cimex lectularius, eggs and first instars. Journal of Visualized Experiments: JoVE, 121, 55092. https://doi.org/10.3791/55092

Delaunay, P. (2012). Human travel and traveling bedbugs. Journal of Travel Medicine, 19 (6), 373-379. https://doi.org/10.1111/j.1708-8305.2012.00653.x

Doggett, SL, Dwyer, DE, Peñas, PF, & Russell, RC (2012). Bed bugs: clinical relevance and control options. Clinical Microbiology Reviews, 25 (1), 164-192. https://doi.org/10.1128/CMR.05015-11

Fountain, T., Duvaux, L., Horsburgh, G., Reinhardt, K., & Butlin, RK (2014). Human-facilitated metapopulation dynamics in an emerging pest species, Cimex lectularius. Molecular Ecology, 23 (5), 1071-1084. https://doi.org/10.1111/mec.12673

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Hinson, KR, Benson, EP, Zungoli, PA, Bridges Jr, WC, & Ellis, BR (2016). Egg Hatch Rate and Nymphal Survival of the Bed Bug (Hemiptera: Cimicidae) After Exposure toInsecticide Sprays. Journal of Economic Entomology, 109 (6), 2495-2499. https://doi.org/10.1093/jee/tow223

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Artemisia princeps, Artemisia japonica (Western Artemisia), Artemisia rupestris (Bitter Artemisia), and Artemisia velutipes (Matricaria) all belong to the Artemisia genus of the Asteraceae family. Many species are extremely common perennial herbs that grow dominantly in small vacant lots from urban areas to mountainous fields. A major characteristic is that the underside of the leaves is cottony and fluffy, and unusually for the Asteraceae family, they are wind-pollinated. However, because their flowers and fruits are inconspicuous, classification is difficult, and they can be hard to distinguish in the wild. The Artemisia genus is a very large group, so you need to consult a field guide for accurate identification, but for the four species, you can roughly distinguish them by the shape of the leaves and the amount of hair. Three of the species are rare on Honshu, with Artemisia princeps being almost dominant. Nowadays, their use seems to be limited to mugwort rice cakes, but Artemisia japonica is commonly used in Okinawa, and the group is actively researched for its medicinal properties. It can also be used in moxibustion. This article will explain the classification, morphology, ecology, and uses of the Artemisia genus.

What are mugwort, wormwood (Artemisia princeps), bitter wormwood, and male wormwood?

Artemisia indica var. maximowiczii, also known as mugwort, is also called Kazuzaki mugwort or mochigusa. While Artemisia princeps is sometimes seen used online, it is a synonym (former scientific name). It is a perennial herb distributed in Honshu, Shikoku, Kyushu, and the Ogasawara Islands of Japan, as well as in Korea, and grows in a wide range of areas from urban centers to mountains and fields (Kanagawa Prefecture Flora Survey Association, 2018).

Artemisia indica var. indica, also known as Okinawa mugwort or Fuchiba, is a perennial herb distributed in Honshu (west of the Kanto region), Kyushu, and the Ryukyu Islands in Japan; Korea, China, Taiwan, Southeast Asia (Thailand, Cambodia, Myanmar, Vietnam, Philippines), and South Asia, growing in areas such as construction sites and slopes along forest roads (Shimotsuke, 2014).

Artemisia absinthium, also known as bitter wormwood, is a perennial plant native to Europe, Russia, the Caucasus, West Asia, and North America, and has escaped cultivation and become naturalized all over the world, including Japan.

Artemisia japonica subsp. japonica var. japonica, also known as male mugwort, is a perennial herb distributed in Hokkaido, Honshu, Shikoku, Kyushu, and the Ryukyu Islands in Japan; as well as in Korea, China, Taiwan, the Philippines, and Afghanistan. It grows in riverbeds, grasslands, forest edges, and railway embankments. Its Japanese name is said to originate from the small size of its seeds.

All of these belong to the Artemisia genus of the Asteraceae family, and are extremely common perennial plants that predominantly grow in small vacant lots from urban areas to mountainous fields. However, Artemisia wormwood is an introduced species.

Morphologically, the underside of the leaves is cottony and fluffy, and the flower heads (inflorescences characteristic of the Asteraceae family) are usually oriented downwards (rarely upwards) and composed of tubular florets.

The most distinctive feature is that while most plants in the Asteraceae family are insect-pollinated, attracting insects with bright colors for pollination, Artemisia species have tubular florets that are wind-pollinated, relying on the wind to carry their pollen.

One theory suggests that this characteristic evolved when the ancestors of the Artemisia genus, which are closely related to the Chrysanthemum genus, moved into arid regions with fewer insects and switched to wind-pollinated flowers.

In fact, this aligns with the fact that Artemisia species can adapt and grow even in dry, concrete-filled areas.

Mugwort and its relatives have a long history of being used for food and medicine. Although they can be found everywhere these days, it seems that their use has decreased. However, I think most Japanese people have eaten mugwort mochi, which is made from mugwort. In Okinawa, mugwort is called "fuuchiba" and, despite its distinctive taste, is commonly eaten.

In addition, Artemisia princeps is also edible, but distinguishing between these plants is often very difficult in the wild, partly because their flowers are inconspicuous and their characteristics are hard to see.

What are the differences between mugwort, wormwood (Artemisia princeps), bitter wormwood, and male wormwood?

There are approximately 30 species of Artemisia in Japan alone, making it quite difficult to distinguish between them.

However, for reference purposes, we will only consider methods of distinguishing between four species here. Among these four species, *Artemisia princeps* and *Artemisia rupestris* can be clearly distinguished by carefully observing their leaves (Kanagawa Prefecture Flora Survey Association, 2018).

First, while mugwort, wormwood, and bitter wormwood have pinnately compound leaves, meaning the leaves are finely lobed like bird feathers, in contrast to muscovado, where the central leaves have shallower lobes and are usually spatulate-wedge shaped. There is a great deal of variation in the leaves, so you will need to examine several leaves, but it should be relatively easy to identify.

Furthermore, while white hairs are prominent on the leaves of Artemisia princeps, Artemisia japonica, and Artemisia glabra, there are almost no white hairs on Artemisia japonica.

Another important taxonomic difference is that while Artemisia princeps, Artemisia japonica, and Artemisia glabra produce both female and hermaphroditic flowers, Artemisia rupestris produces only female flowers and not hermaphroditic flowers. However, confirming this is limited to the flowering season and would be difficult for the average person.

Regarding the remaining three species, the differences are that in Artemisia princeps and Artemisia japonica, white hairs grow only on the underside, the pinnately compound leaves are not very finely divided, and the tips of the compound leaves are relatively sharp, while in Artemisia rupestris, white hairs grow on the upper surface as well, the pinnately compound leaves are more finely divided, and the tips of the compound leaves are relatively rounded.

Therefore, you can clearly see that wormwood is whitish in appearance.

The two species mentioned above are overwhelmingly rarer than mugwort, and the dominant species growing in towns is usually mugwort.

Artemisia japonica is more resistant to salt and drought damage than Artemisia sulphureus and can be found growing on coastlines (Iriyama, 2006).

What is the difference between mugwort and yomogi (Erigeron annuus)?

The most difficult to grow are mugwort and aster.

The only difference between Artemisia princeps and Artemisia japonica, according to field guides, is that Artemisia princeps has flower heads that are 1.2–1.8 mm in diameter, while Artemisia japonica has flower heads that are 1.8–2.5 mm in diameter. In other words, the parts that look like flowers (which are actually clusters of flowers) are larger in Artemisia princeps.

Therefore, it may be almost impossible to distinguish them outside of their flowering season.

While *Erigeron annuus* is sometimes described as a variety with wider leaf lobes, which could potentially help distinguish it, there is no specific description of how wide the leaf lobes must be to identify *Erigeron annuus*.

From a distribution standpoint, it seems that we can currently confirm that the plants found east of the Kanto region in Honshu are Artemisia princeps, while those found in Okinawa are Artemisia nipponica.

However, there is a clear difference in taste; Western mugwort is less bitter and has a softer texture, making it more suitable for eating.

While distinction is important from a culinary standpoint, mugwort and wormwood are broadly considered varieties within the species Artemisia indica. In some countries and eras, classifications treat mugwort, wormwood, and Artemisia japonica as a single species, indicating that they are an extremely closely related group (Shimono, 2014).

Are there any other similar species?

As mentioned above, there are many varieties, but if you carefully examine the shape of the leaves, you'll find that there are surprisingly few similar species. Nevertheless, you might still find it quite difficult.

Artemisia montana resembles mugwort and magnolia, but unlike them, it has almost no pseudostipules at the base of the petiole, and its flower heads are bulbous and bell-shaped. "Pseudostipules" are leaf-like structures that extend to the left and right from the base of the petiole on the plant body. This is relatively easy to identify, but the flower heads are frankly too ambiguous. It is common in Hokkaido and is usually found in high-altitude mountainous areas on Honshu, so those found in lowlands are likely to be large-sized mugwort.

Artemisia japonica var. lacinifolia resembles Artemisia japonica, but unlike Artemisia japonica, its leaves are pinnately deeply lobed, and the lobes are linear-lanceolate.

Gray wormwood (Artemisia sieversiana) resembles bitter wormwood, but unlike bitter wormwood, its leaf lobes gradually narrow and have sharp tips.

Artemisia vulgaris resembles mugwort and asterias, but is not currently listed in Japanese botanical guides. However, overseas studies have indicated its distribution in Japan, and its actual distribution is still not well understood (Shimono, 2014).

What are the differences in how to use mugwort, wormwood (Artemisia princeps), bitter wormwood, and male wormwood?

What are some uses for mugwort?

Mugwort has a distinctive aroma, and the young shoots picked in spring can be boiled and used in dishes such as blanched greens, soups, or even in kusa mochi (mugwort rice cakes) or deep-fried (Odachi & Hiyama, 2013). It can also be used to make mugwort tea.

Kusa mochi (known as yomogi mochi in the Kansai region) is said to have originated in the Heian period as a rice cake kneaded with cudweed, one of the seven spring herbs, but by the Edo period, the use of mugwort became established (Yamashita, 2019).

Moxibustion, or "kyu," uses moxa, which is an important part of the traditional East Asian medicine practice. Moxa is made from dried mugwort leaves with the downy hairs on the underside (Oda, 1984; Odachi & Hiyama, 2013). In this practice, moxa is burned on selected areas of the body surface (skin) to provide thermal stimulation, which is used for disease prevention and treatment. However, Artemisia montana (Japanese wormwood) is also used in some cases. Furthermore, since the plant distributed in China is not mugwort but Korean wormwood (Artemisia argyi), it is highly likely that this is used in countries other than China.

It has many medicinal uses, and its leaves are used as a crude drug called "gaiyo," which has hemostatic properties. Some of the gaiyo is actually mugwort, which is called Korean mugwort in China.

Young shoots and budding plants, after being dried and brewed into a tea, are traditionally used as a folk remedy for stomach ailments, abdominal pain, diarrhea, anemia, and cold sensitivity. More mature plants are also dried and added to bathwater as a bath additive to relieve lower back pain and hemorrhoids.

Mugwort is known to be highly nutritious, particularly rich in minerals and vitamins. Among vegetables, it ranks third in potassium content (after Swiss chard and parsley), second in iron content (after parsley), and eighth in beta-carotene content (Ando et al., 2022). Furthermore, mugwort is known to have strong antioxidant properties due to its high content of vitamins and polyphenols.

Its unique components include cineole, thujone, β-caryophyllene, borneol, and camphor (Odachi & Hiyama, 2013).

How can I use Artemisia princeps?

Although *Artemisia princeps* has a different distribution than *Artemisia japonica*, and is therefore used in different regions, its uses are very similar to those of *Artemisia princeps*.

In the Western Himalayas, it is called "thitepati" and is used by indigenous people to treat indigestion, chronic fever, and other liver diseases (Koul et al., 2017). In Nepal, the juice of this plant is used to treat dysentery, abdominal pain, and diarrhea. The young leaves are cooked and eaten with barley, adding color and flavor to rice.

For food, the Garo people (a tribe living in the Noklek Biosphere Reserve in Meghalaya, India) eat the tender sprouts as a vegetable.

Nepalis use the juice of the leaves to treat skin diseases, and the dried leaves and flowers are used as an insect repellent.

In Okinawa, it is called Fuchiba, and in the Ryukyuan language, it means "ba (leaf) that cures Fuchi (wind: illness)," which translates to "wind leaf" in Japanese. It has been widely used in households as a medicinal herb because it is believed to be effective in reducing fever, gastrointestinal diseases, and gynecological diseases (Japan Society for Food Science and Technology, 2021).

In cooking, it is often used in dishes such as Fuchiba Jushi (rice cooked with mugwort) and Boroboro Jushi (rice porridge with mugwort) (Watanabe, 2008; Japan Society for Food Science and Technology, 2021). Jushi refers to rice porridge. Its use varies by region.

In addition, it is sometimes added raw to Okinawa soba, and when used in hijaa-jiru (goat soup), it serves to mask the odor.

The reason why Artemisia japonica can be readily eaten raw may be because its leaves are more fragrant than those of Artemisia sylvestris (Yamashita, 2019) and easier to eat.

Chemically, it contains volatile oils such as β-thujone, hernialin, 1,8-cineole, estragole, savinyl acetate, ciscrisanthenyl acetate, dabanone oil, and terpineol, and possesses antifungal properties (Koul et al., 2017). Two novel compounds, trans-ethyl cinnamate and piperitone, have been isolated by chromatographic distillation.

How can wormwood (Artemisia princeps) and mugwort (Artemisia rupestris) be used?

Wormwood is an introduced species and therefore has no traditional uses in Japan, but it has a history of being used in Europe and Turkey for medicinal purposes similar to mugwort (Koul et al., 2017). It is too bitter to eat raw and is used in the herbal liqueur "absinthe."

Scientifically, its antiparasitic, antibacterial, antioxidant, and hepatoprotective properties have been proven, and experimentally, wormwood essential oil has shown antibacterial activity against budding yeast and Candida albicans.

Although Artemisia princeps is not widely used in Japan, the same subspecies found overseas has been widely used in folk medicine to treat eczema and fever.

How is pollination done?

Artemisia plants typically produce large conical inflorescences at the tips of their stems, bearing numerous small flower heads that hang downwards. The flower head is a structure unique to the Asteraceae family; it is not a single flower, but rather an inflorescence (a cluster of flowers). It consists of countless tiny flowers (florets) that may possess stamens and pistils.

There are two types of florets: ray florets and disc florets. However, in mugwort, only disc florets are present, and within these disc florets, the inner part of the flower head contains bisexual flowers (with both stamens and pistils), while the outer part contains female flowers (with only pistils).

As mentioned above, it is unusual for a member of the Asteraceae family to be wind-pollinated (Shimono, 2014; Yamashita, 2019). However, insect-pollinated varieties were also confirmed in 2022 (Hussain et al., 2024).

Regarding pollen, while animal-pollinated pollen sometimes has spines on its surface, Artemisia pollen is smooth, which is thought to be advantageous when dispersed by wind (Bolick, 1990).

What are the seed dispersal methods?

The fruits of the Artemisia genus are obovate achenes, glabrous or hairy. They lack pappus or have very short hairs. The seeds are contained within the very small achenes, resulting in a very high yield.

Therefore, it is thought that there is no special method of seed dispersal, but because the fruit and the seeds inside are very small and the yield is very high, it is thought that, at least in the case of wormwood, it is easily dispersed by water and animals in addition to gravity (Goud et al., 2015).

References

Ando, Masaya; Ogata, Ayano; Kuronuma, Takanori; Matsumoto, Takeshi; and Watanabe, Hitoshi. (2022). Evaluation of domestically produced mugwort varieties for food use. Journal of the All Japan Acupuncture and Moxibustion Society, 72 (1), 68-78. https://doi.org/10.3777/jjsam.72.68

Bolick, MR (1990). The pollen surface in wind-pollination with emphasis on the Compositae. In M. Hesse, & F. Ehrendorfer (Eds.), Plant Systematics and Evolution Vol. 5: Morphology, Development, and Systematic Relevance of Pollen and Spores (pp. 39-51). Springer. https://doi.org/10.1007/978-3-7091-9079-1_4

Goud, BJ, Dwarakanath, V. & Swamy, BC (2015). A review on history, controversy, traditional use, ethnobotany, phytochemistry and pharmacology of Artemisia absinthium Linn. International Journal of Advanced Research in Engineering and Applied Sciences, 4 (5), 77-107. https://indianjournals.com/article/ijareas-4-5-008

Hussain, M., Thakur, RK, Khazir, J., Ahmed, S., Khan, MI, Rahi, P., … & Mir, BA (2024). Traditional uses, phytochemistry, pharmacology, and toxicology of the genus Artemisia L.(Asteraceae): A high-value medicinal plant. Current Topics in Medicinal Chemistry, 24 (4), 301-342. https://doi.org/10.2174/1568026623666230914104141

Iriyama, Yoshihisa. (2006). Artemisia japonica. Journal of the Japanese Society of Landscape Architecture, 31 (4), 449. ISSN: 0916-7439, https://www.jsrt.jp/pdf/dokomade/31-4otokoyomogi.pdf

The Japanese Society for Food Science and Technology. (2021). Traditional Japanese Home Cooking: Donburi, Zosui, and Okowa. Agricultural, Forestry and Fisheries Culture Association. ISBN: 9784540191824

Kanagawa Prefecture Flora Survey Association. (2018). Kanagawa Prefecture Flora 2018 Electronic Edition. Kanagawa Prefecture Flora Survey Association. ISBN: 9784991053726,https://flora-kanagawa2.sakura.ne.jp/efloraofkanagawa.html

Koul, B., Taak, P., Kumar, A., Khatri, T., & Sanyal, I. (2017). The Artemisia genus: A review on traditional uses, phytochemical constituents, pharmacological properties and germplasm conservation. Journal of Glycomics & Lipidomics, 7 (1), 142. https://doi.org/10.4172/2153-0637.1000142

Odachi, Junko & Hiyama, Keiichiro. (2013). On the effects and uses of mugwort (Artemisia princeps). Tezukayama University Faculty of Contemporary Life Studies Bulletin, 9, 1-9. ISSN: 1349-7073, https://tezukayama.repo.nii.ac.jp/records/777

Oda, Ryuzo. (1984). Research on moxa (I): Recent manufacturing processes and the raw material, mugwort. Journal of the All Japan Acupuncture and Moxibustion Society, 33 (4), 427-430. https://doi.org/10.3777/jjsam.33.427

Shimono, Yoshiko. (2014). Artemisia indica Willd. var. maximowiczii (Nakai) H. Hara: From the perspective of a greening plant. Grass and Greenery, 6, 23-31. https://doi.org/10.24463/iuws.6.0_23

Yamashita, Tomomichi. (2019). Mugwort in Everyday Life. Nature Conservation, 568, 18-19. ISSN: 0386-4138, https://www.nacsj.or.jp/magazine/14752/

Watanabe, Yoshio. (2008). Dictionary of Okinawan Folklore. Yoshikawa Kobunkan. ISBN: 9784642014489

Hydrocotyle sibthorpioides, Hydrocotyle japonica, Hydrocotyle umbellata, and Hydrocotyle kobus are all members of the Hydrocotyle genus in the Araliaceae family. They are perennial herbs that creep along the ground in slightly shaded areas from mid-to-forests to woodlands, and are notable for their very small, nearly orbicular simple leaves. However, their flowers and fruits are small and inconspicuous, so they are often overlooked and relatively difficult to distinguish. However, they can generally be distinguished by checking the amount of hair on the upper and lower surfaces of the leaves and the degree of leaf lobes. The insects that visit the flowers are not well studied, and while flies and ants are strong candidates, they are not yet known. This article will explain the classification, morphology, and ecology of the Hydrocotyle genus.

What are *Hydrocotyle japonica*, *Hydrocotyle sibthorpioides*, *Hydrocotyle japonica*, and *Hydrocotyle sibthorpioides*?

Hydrocotyle sibthorpioides, also known as "blood-stopping grass," is a perennial herb that is very common and grows along roadsides and in gardens, distributed in Honshu, Shikoku, Kyushu, the Ryukyu Islands, and the Ogasawara Islands of Japan; the southern Korean Peninsula; Taiwan; China; Vietnam; Budan; India; Nepal; and Africa (Kanagawa Prefecture Flora Survey Association, 2018).

Hydrocotyle yabei var. yabei, also known as Himechidome (small blood-stopping grass), is a perennial herb that is distributed in Hokkaido (Oshima Subprefecture), Honshu, Shikoku, and Kyushu in Japan, as well as Jeju Island (South Korea), and is fairly common in the forest floor from hilly to mountainous areas.

Hydrocotyle maritima, also known as Nohidome (wild blood stopper), is a perennial herb commonly found in forest edges, field edges, and wetlands, distributed across Honshu, Shikoku, Kyushu, the Ryukyu Islands, and the Ogasawara Islands in Japan; the Korean Peninsula; and China.

Hydrocotyle ramiflora, also known as "large hemostatic flower," is a perennial herb commonly found in grasslands, lawns, and field edges in Japan (Hokkaido, Honshu, Shikoku, and Kyushu) and the Korean Peninsula.

Both belong to the genus Hydrocotyle in the family Araliaceae. They are perennial herbs that creep along the ground in slightly shaded areas from urban areas to forests, and are notable for their very small, almost orbicular, simple leaves. They also have the characteristic of having two schizocarps.

The Japanese name "Chido-megusa" comes from the fact that applying the juice of crushed leaves to small wounds stops bleeding, and I-sesamin is considered to be an active ingredient (Osawa, 1999). It has also been traditionally used medicinally for infectious diseases around the world, and scientific evidence is being proven to support this (Hazarika et al., 2021).

However, because they are so inconspicuous, they are often overlooked, and their flowers and fruits are also plain, making them very difficult to distinguish at a glance.

What are the differences between *Hydrocotyle japonica*, *Hydrocotyle sibthorpioides*, *Hydrocotyle japonica*, and *Hydrocotyle sibthorpioides*?

While the four species can be distinguished to some extent by knowing the shape of their leaves, more accurate identification is possible by recording both the upper (surface) and lower (back) surfaces of the leaves (Kanagawa Prefecture Flora Survey Association, 2018).

First, in *Hydrocotyle japonica* and *Hydrocotyle sibthorpioides*, the entire stem creeps along the ground and the leaf blades are thin and hairless on both sides, whereas in *Hydrocotyle japonica* and *Hydrocotyle sibthorpioides*, the tip of the stem grows obliquely upward and the leaf blades are thick and hairy on both sides or the underside.

Regarding *Hydrocotyle japonica* and *Hydrocotyle sibthorpioides*, *Hydrocotyle japonica* has shallowly lobed leaf margins, somewhat rounded serrations, about a dozen flowers, and a truncate fruit base, while *Hydrocotyle sibthorpioides* has deeply lobed leaf margins, nearly triangular serrations, fewer than 10 flowers, and a heart-shaped fruit base.

Regarding *Hydrangea macrophylla* and *Hydrangea serrata*, *Hydrangea macrophylla* has deeply lobed leaf margins, a nearly pentagonal outline, hairy veins on the upper surface of the leaf, and a petiole longer than its corresponding pedicel, while *Hydrangea serrata* has very shallowly lobed leaf margins, a nearly circular outline, a hairless upper surface of the leaf, and a petiole shorter than its corresponding pedicel.

There are various factors to consider, but ultimately, focusing on the hairs and incisions of the leaf blade should suffice. The hairs on the leaves of the Hydrocotyle genus are erect and clearly visible in photographs.

Generally speaking, it's worth noting that *Cydonia oblonga* is often found in urban areas, while the other three species are found in areas with a relatively high degree of naturalness.

Are there any other similar species?

There is a form of *Hydrangea macrophylla* with large leaf blades and a narrow base, which is sometimes classified as *Hydrangea macrophylla var. japonica*, but some believe that the leaf shapes are continuous and difficult to distinguish (Kanagawa Prefecture Flora Survey Association, 2018).

Among the native species, there is also a species called Hydrocotyle javanica, but it can be easily distinguished by its unique characteristic of having short, curled hairs all over the flower stalks and leaf stalks, which is not seen in other species.

The genus Hydrocotyle includes several species that have attracted attention worldwide as invasive species that have escaped the trade and become naturalized.

Hydrocotyle verticillata var. triradiata, also known as water mushroom or water coin, is a plant that has escaped cultivation in aquariums and become naturalized. It can be easily distinguished by its nearly circular leaf blade and the shield-shaped petiole attached to the center of the leaf blade.

The Brazilian pennywort, Hydrocotyle ranunculoides, a designated invasive alien species, grows in water and can be easily distinguished by its succulent flesh and thick petioles.

How does pollination occur? What insects visit very small flowers?

It is unclear whether this is true for all species of the genus Hydrocotyle, but in introduced species such as Hydrocotyle brevifolia and Hydrocotyle sibiricum, vegetative reproduction is mainly carried out by stolons (Nakajima and Oki, 2017).

However, some species reproduce sexually through cross-pollination in order to incorporate genes from other individuals and become more resilient to environmental changes.

The genus Hydrocotyle blooms from June to October, producing one to several single umbels. The flowers are very small, about 2 mm in diameter, and typically consist of 5 petals, 5 stamens, and 2 pistils.

While there is a lack of research on the pollination methods of the genus Hydrocotyle, one study, based on observations, literature, and flower morphology, treats it as being pollinated by flies, along with the genus Stilbocarpa (Garcia et al., 2022).

Indeed, the very small flowers of the Hydrocotyle genus could be preyed upon by small fly-like insects.

Records for individual species are even more scarce.

There are records of the hoverfly Paragus jozanus and the bee species Lasioglossum sp. visiting the flowers of Hydrangea macrophylla (Yamazaki & Kato, 2003).

There are records of ants and thrips visiting the flowers of *Hydrocotyle sibiricum* (Ushijima & Ushijima, 2014).

Although insects occasionally visit the flowers of *Polytrichum commune*, self-pollination is considered to be the primary method of pollination (Ruhsam et al., 2025).

While I'm unsure about other species, I've also observed ants visiting the flowers of the Japanese honeysuckle.

Ants are generally thought to contribute very little to cross-pollination, and there are two reasons for this.

Firstly, ants tend to visit only the same flowers or flowers from the same plant, and feed only on nectar. Therefore, they are often considered to have no contribution to pollination, or if they do, it is only self-pollination or neighboring flower pollination, and they do not contribute to cross-pollination (Rostás et al., 2018). Even when self-pollination or neighboring flower pollination occurs, the subsequent seed germination rate and seedling mortality rate may be high.

Furthermore, it has been found that the secretions from the metapleural gland, which ants release to protect themselves from microbial infections, are also effective against pollen, reducing its germination rate (Dutton & Frederickson, 2012).

However, since ants contribute to pollination in species that are self-compatible and capable of self-pollination (de Vega & Gómez, 2014), and since species of the genus Hydrocotyle are known to be self-compatible and for which self-pollination is the primary pollination strategy (Nery, 2019), I am paying close attention to the possibility that ants contribute to pollination in the genus Hydrocotyle.

What are the seed dispersal methods?

There appears to be no comprehensive study on the seed dispersal methods of the genus Hydrocotyle, but one study treats Hydrocotyle sibthorpioides and Hydrocotyle macrophylla as simply dispersing by gravity (Nishida et al., 1993).

On the other hand, since water-flow dispersal is also used for invasive species such as Brazilian pennywort and prickly pear (Nakajima and Oki, 2017), it is possible that similar methods exist for native species as well.

References

de Vega, C., & Gómez, JM (2014).

Dutton, EM, & Frederickson, ME (2012). Why ant pollination is rare: new evidence and implications of the antibiotic hypothesis. Arthropod-Plant Interactions, 6 (4), 561-569. https://doi.org/10.1007/s11829-012-9201-8

Garcia, JE, Hannah, L., Shrestha, M., Burd, M., & Dyer, AG (2022). Fly pollination drives convergence of flower coloration. New Phytologist, 233 (1), 52-61. https://doi.org/10.1111/nph.17696

Hazarika, I., Mukundan, GK, Sundari, PS, & Laloo, D. (2021). Journey of Hydrocotyle sibthorpioides Lam.: From traditional utilization to modern therapeutics—A review. Phytotherapy Research, 35 (4), 1847-1871. https://doi.org/10.1002/ptr.6924

Kanagawa Prefecture Flora Survey Association. (2018). Kanagawa Prefecture Flora 2018 Electronic Edition. Kanagawa Prefecture Flora Survey Association. ISBN: 9784991053726

Nakajima, Yoshitaka & Oki, Yoko. (2017). Comparison of cold tolerance and seed reproduction characteristics of three species of the genus Hydrocotyle, an introduced aquatic plant. Weed Research, 62 (2), 19-24. https://doi.org/10.3719/weed.62.19

Nery, EK (2019). An integrated taxonomic approach to the Hydrocotyle stella Pohl ex DC.(Araliaceae) complex from the brazilian atlantic forest [Master's thesis, Federal University of Santa Catarina]. https://repositorio.ufsc.br/handle/123456789/211445

Nishida, Tomoko; Harashima, Tokuichi; and Sato, Kenji. (1993). Weed growth in pastures with different uses. Research Report of the Grassland Research Station, 47, 45-54. https://agriknowledge.affrc.go.jp/RN/2010490600

Osawa, Toshihiko. (1999). Functional properties of lignans. Journal of the Japan Oil and Lime Chemical Society, 48 (10), 1041-1048. https://doi.org/10.5650/jos1996.48.1041

Rostás, M., Bollmann, F., Saville, D., & Riedel, M. (2018). Ants contribute to pollination but not to reproduction in a rare calcareous grassland forb. PeerJ, 6, e4369. https://doi.org/10.7717/peerj.4369

Ruhsam, M., Hollingsworth, PM, & Darwin Tree of Life Consortium. (2025). The genome sequence of the Marsh Pennywort, Hydrocotyle vulgaris L. (Apiales: Araliaceae). Wellcome Open Research, 10, 370. https://doi.org/10.12688/wellcomeopenres.24582.1

Ushijima, Kiyoharu & Ushijima, Tomiko. (2014). Flowering morphology of Hydrangea macrophylla. Kyousei no Hiroba, 9, 63-66. ISSN: 1881-2147, https://www.hitohaku.jp/publication/book/kyousei9_p63-66.pdf

Yamazaki, K., & Kato, M. (2003). Flowering phenology and anthophilous insect community in a grassland ecosystem at Mt. Yufu, western Japan. Contributions from the Biological Laboratory, Kyoto University, 29, 255-318. http://hdl.handle.net/2433/156407

In Japan, except in some regions, eating insects is extremely rare, and it can be said that it is almost unheard of among the younger generation, especially in urban areas.

While some advocate for eating insects to prepare for food shortages, cries of "Absolutely not!" are heard, mainly on social media. Even though I work with insects, I also feel a sense of pity for them and have reservations about eating them.

That being said, the truth is that, unintentionally, Japanese people eat insects (or components extracted from them) every day. Representative examples include cochineal, which contains carminic acid produced by the cochineal insect, and shellac, which is made by heat treatment or solvent extraction of lac, produced by the lac insect.

To put it simply, cochineal is used as a pure dye in food and cosmetics, lac is used as a dye in food, and shellac is used as a wax in many applications such as adhesives, food polishing agents, wood finishes, and SP records.

Cochineal is generally safe, but it's important to be aware that in rare cases, people who regularly use cosmetics containing cochineal may experience allergic reactions.

The reason cochineal continues to be used despite containing insects is likely because safe and inexpensive artificial colorings have yet to be found.

This article will explain cochineal insects and lac insects, as well as the components they produce.

What is the difference between cochineal insects and lac insects?

First, let's clarify the differences between cochineal insects and lac insects, which are often confused.

The cochineal insect (also known as the cochineal insect), Dactylopius coccus, belongs to the family Dactylopiidae within the superfamily Coccoidea and is distributed from the southwestern United States through Mexico to the temperate regions of South America (Schowalter, 2025). It is now sometimes cultivated in China. It uses prickly pear cacti (Cactaceae) as its host, inserting its stylets into the phloem tubes (tubes that transport sugars produced by photosynthesis throughout the plant) and feeding on the phloem sap.

On the other hand, the lac insect Kerria lacca (Laccifer lacca is a synonym) is classified in the family Kerriidae within the superfamily Coccoidea and is distributed in China, South Asia (India, Pakistan, Bangladesh), and Southeast Asia (Indonesia, Vietnam, Laos, Myanmar) (Watanabe, 2003; Takekawa, 2010; Bashir et al., 2022). Its hosts are extremely diverse, with over 400 plant species reported worldwide, but commercially, three species are used: Butea monosperma (Fabaceae), Schleichera oleosa (Sapindaceae), and Ziziphus mauritiana (Rhamnaceae). Like the lac insect, it lives by inserting its stylets into the phloem tubes and feeding on the phloem sap.

Although they both cling to plants in a similar way, cochineal insects are originally from the Americas, while lac insects are found in Eurasia. You can see that the plants they utilize and their habitats are completely different.

The components produced are also different.

Cochineal insects produce carminic acid, which is both a defensive substance and a pigment, while lac insects produce a waxy substance called lac, which contains laccaic acid as a pigment.

Why did the cochineal insect evolve to produce carminic acid?

It is believed that carminic acid was originally secreted by the cochineal insect to protect itself from carnivorous insects such as ants, ladybugs, and lacewings, as well as microorganisms (Schowalter, 2025). The defense provided by carminic acid is strong, and very few species prey on it.

However, some insects are known to still prey on cochineal insects. The larvae of the carnivorous moth Laetilia coccidivora, a member of the Pyralidae family, are known to prey on cochineal insects by spitting out a sac containing carminic acid. However, even in this case, their survival rate, development rate, and reproduction rate are significantly worse than when they feed on cochineal insects that do not contain carminic acid.

While carminic acid is merely a pigment for humans, it is actually an important component for cochineal insects.

The fact that cochineal insects themselves can turn red is thought to be due to carminic acid, and it is possible that this is an "honest signal" warning color, intended to convey "the redder, the more poisonous!" by possessing both pigment and defense properties, but this has not been thoroughly investigated. Examples of warning colors that serve as honest signals by combining pigment and antioxidant properties are well known (Blount et al., 2009).

What are the differences in the uses of cochineal lac and shellac?

Cochineal insects are killed with boiling water and dried to produce "black cochineal," and crushing black cochineal yields "cochineal," which contains carminic acid. For dyeing purposes, carminic acid is further chemically reacted to synthesize "carmine" (Akiyama & Sugimoto, 2014; Schowalter, 2025).

On the other hand, the lac produced by the lac insect initially clumps together on the branches of the host plant, but the lac removed from the branch is called "stick lac" (Toko and Komashiro, 2007). This stick lac can be washed and dried to produce what is called "seed lac," and further heat treatment or solvent extraction can produce "shellac," a pure wax that does not contain insect remains and has reduced or eliminated laccaic acid.

It's important to note that rack and shellac are different things.

How do these ultimately produced ingredients differ in their uses?

To put it simply, cochineal is used as a pure dye in food and cosmetics, lac is used as a dye in food, and shellac is used as a wax in many applications such as adhesives, food polishing agents, wood finishes, and SP records.

Because cochineal produces a vibrant red color, it was originally used for dyeing cloth, and there are records of its use in Central and South America from at least 600 AD (Schowalter, 2025). When Columbus visited the Americas during the Age of Discovery, it was highly valued by European nobility because of its superior strength and durability compared to older dyes, and it eventually became inexpensive and spread throughout the world. It was also introduced to Japan through trade with the West during the Momoyama and Edo periods, and was used by Sengoku warlords (Toko and Komashiro, 2007). However, with the advent of aniline dyes, its use for dyeing cloth declined, and other uses were developed.

In Japan today, cochineal is used as a food coloring agent in soft drinks, strawberry milk, alcohol, shaved ice syrup, confectionery, ham, sausages, and fish cakes, as well as in cosmetics such as lipstick, lip balm, blush, eyeshadow, and nail polish, and in art supplies. Note that in Japan, the cochineal used in food products is carminic acid, while in cosmetics it is carmine (Inomata, 2025).

Lac still contains a lot of laccaic acid, so it is used as a fabric dye and is known as lac dyeing (purple mineral dyeing) (Takekawa, 2010). Around 2000 BC, it was used in China and India as a dye and as a medicine called myrrh (traditional Chinese medicine). It had already been introduced to Japan during the Nara period and has been found in the Shōsōin Treasury (Toko and Komashiro, 2007). However, its use declined with the advent of aniline dyes and Western medicine.

In modern Japan, lac is added to food products and used to color sweets, bean paste, bacon, sausages, noodles, processed seafood, and jams.

Shellac was originally used as a finishing material because of its excellent properties for protecting and polishing wood. However, in the early 20th century, the developing electrical industry recognized its excellent properties as an electrical insulator, leading to increased demand. However, in 1907, when American Leo Baekeland invented Bakelite as a substitute, its use in that application declined (Le Couteur & Burreson, 2003).

However, shellac's other uses have expanded in many directions, and in Japan today it is used in countless ways, including paints, adhesives, varnishes for stringed instruments and wooden furniture, granular chocolates and gums that don't stain hands, pharmaceutical tablets, a coating agent for roasted chestnuts, and SP records (Takekawa, 2010).

These insects have truly been supporting society from ancient times to the present day, constantly changing their form along the way.

Do Japanese people really eat cochineal insects? From the cultivation of cochineal insects to their eventual appearance on the dinner table as a food coloring agent.

Some people might wonder, "Do Japanese people actually eat cochineal insects?"

In other words, regardless of whether cochineal is used, the point is that it's merely an extracted chemical component, and not the cochineal insect itself. (Some people might find that off-putting, though...)

Unfortunately (?), we can proudly say that the Japanese eat scale insects (Akiyama & Sugimoto, 2014; Schowalter, 2025).

Cochineal insects harvested from prickly pear cacti are killed by soaking them in hot water or exposing them to sunlight or heat, and then dried for preservation until they reach approximately 301 TP3T of their raw weight. This is "black cochineal."

The powder produced by crushing black cochineal is called "cochineal." Approximately 70,000 insects are needed to produce one pound (0.45 kilograms) of cochineal dye (Miller, 2022).

When cochineal is boiled in ammonia water or sodium carbonate solution and alum is added, a red aluminum carminate precipitate forms. This aluminum carminate is "carmine."

Furthermore, by adding other ingredients such as tin chloride, citric acid, borax, and lime, you can create a variety of colors ranging from pink to purple.

In other words, it's almost certain that whole insects are being crushed and then applied to or incorporated into food and cosmetics.

On the other hand, while lac insect lacs also contain insect bodies, shellac consists almost entirely of its chemical components.

Are cochineal scale insects disgusting?

Whether or not cochineal insects are considered disgusting is, of course, subjective, but there are several factors that contribute to that perception.

First, scale insects typically infest leaves in dense clusters and produce a cottony waxy substance. This is thought to protect against moisture loss, excessive sunlight exposure, and predators such as ants, but it is what makes the leaves look unsightly.

Furthermore, in order to excrete the excess sugar absorbed through the phloem (and also as a reward for ants guarding them), the plant "urinates" (diabetes), which gets on the leaves, creating a sticky, viscous substance, and weakening the plant itself, resulting in an even dirtier appearance.

But eccentric people like me think, "It's so small and cute!"

Furthermore, you could say that it's thanks to scale insects that you can put on makeup while enjoying red drinks and sweets like macarons, and then take and post sparkling, "Instagrammable" photos on social media like Instagram.

Therefore, rather than simply dismissing them as "disgusting," I think it's not a bad idea to show gratitude and respect to those who provide us with food. It's certainly not a pleasant experience for the cochineal insects themselves, who are the ones being eaten. (Although, there's also the perspective that they are being bred and thus the species is surviving as a result.)

While it may evoke a physiological aversion, insects and cosmetics are surprisingly closely related, as evidenced by the use of galls (five-grain galls, sumac ear galls) of the sumac aphid Schlechtendalia chinensis for teeth blackening in Japanese history (Ezure et al., 1987).

What are the dangers of cochineal? Does it cause allergies?

However, there is also the practical problem of cochineal insects: the existence of allergies (Akiyama & Sugimoto, 2014; Inomata, 2025).

There are multiple patterns of cochineal allergies.

The first type is occupational inhalation exposure, where workers who are routinely exposed to cochineal dye or carmine through inhalation, such as those engaged in extracting dye from cochineal insects or handling carmine in cosmetics factories, develop allergies.

The second type is those who exhibit skin symptoms caused by cosmetics containing cochineal.

The third type is caused by oral ingestion of foods containing cochineal.

The worst-case scenario is a combination of the second and third types, where applying cosmetics containing cochineal to the face causes the immune system to mistakenly perceive the cosmetic as a "foreign substance that attacks the human body!" and memorize its molecular structure (immunological memory). The next time food containing cochineal is consumed, the immune system overreacts and attacks the body itself. This is called "anaphylactic shock."

Many researchers believe that the cause of this reaction is not carmine from cochineal, but rather residual proteins derived from the body fluids of the cochineal insect that are involved in the manifestation of IgE-mediated allergic symptoms. However, there are also reports of reactions to carmine, so there are various theories.

It is believed that this system originally evolved to react to parasites (Palm et al, 2012). In other words, if a protein is the cause, then this can be rephrased as a reaction that occurs because our bodies mistakenly identify cosmetics containing cochineal insect fluid as "parasites!"

While this may sound quite frightening, despite its widespread use, only 22 cases have been reported in Japan since it began to be documented in academic papers in Japan until 2018, and there have been no deaths (Takeo et al., 2018).

However, it's possible that the lack of awareness is the reason why this condition is occurring more frequently than it actually is, so if you feel anything unusual, be sure to consult a doctor.

Why is cochineal still being used?

Why is cochineal, which is considered "disgusting" and potentially causes allergic reactions, still being used?

In fact, there was a period when artificial red coloring was used, but from around the 1970s, reports on the relationship between coloring and hyperactivity in children, as well as cell and animal studies suggesting that certain dyes may increase the risk of cancer, began to emerge, and health concerns about these synthetic dyes started to grow (Miller, 2022).

These concerns ultimately led to the banning of some dyes, such as Red No. 2 and Red No. 4. However, some of these harmful effects were later revoked.

As a result, naturally derived colorants such as carminic acid have begun to gain popularity.

Natural colorants have a very long history, which can be considered to guarantee their safety to some extent. Furthermore, because the manufacturing process is already established, it is possible to produce them at a lower cost, both in terms of time and money.

However, in addition to the reasons mentioned above, there is a growing number of vegans, vegetarians, and animal rights activists in the United States who do not want to accidentally consume insect-derived products.

Furthermore, using large quantities of prickly pear cacti does not necessarily result in good production efficiency.

Therefore, methods for artificial synthesis are being researched, but practical application is still some time away.

References

Akiyama, Hiroshi & Sugimoto, Naoki. 2014. Food allergies caused by cochineal dye and carmine intake. Pharmacia 50(6): 522-527. https://doi.org/10.14894/faruawpsj.50.6_522

Bashir, NH, Chen, H., Munir, S., Wang, W., Chen, H., Sima, YK, & An, J. 2022. Unraveling the role of lac insects in providing natural industrial products. Insects 13(12): 1117. https://doi.org/10.3390/insects13121117

Blount, JD, Speed, MP, Ruxton, GD, & Stephens, PA 2009. Warning displays may function as honest signals of toxicity. Proceedings of the Royal Society B: Biological Sciences 276(1658): 871-877. https://doi.org/10.1098/rspb.2008.1407

Ezure, T., Katsura, K., Ten, M., Taguchi, H., Ikeda, M., Matsuzaki, A., & Suzuki, T. 1987. Concept and Case Reports of Ohaguro (Teeth Blackening). Iwate Medical University Dental Journal 12(2): 217-221. https://doi.org/10.20663/iwateshigakukaishi.12.2_217

Inomata, Naoko. 2025. Cochineal dye allergy. Allergy 74(3): 174-176. https://doi.org/10.15036/arerugi.74.174

Le Couteur, PC, & Burreson, J. 2003. Napoleon's buttons: How 17 molecules changed history. Tarcher, 384pp. ISBN: 9781585422203 [=2011. Spices, explosives, pharmaceuticals—17 chemical substances that changed world history. Chuokoron-Shinsha, Tokyo. 368pp. ISBN: 9784120043079]

Miller, BJ 2022. Cochineal, a red dye from bugs, moves to the lab. Knowable Magazine. ISSN: 2575-4459, https://doi.org/10.1146/knowable-032522-1

Palm, NW, Rosenstein, RK, & Medzhitov, R. 2012. Allergic host defences. Nature 484(7395): 465-472. https://doi.org/10.1038/nature11047

Schowalter, TD 2025. Ecology, use, and management of cochineal insects (Hemiptera: Dactylopiidae). Journal of Integrated Pest Management 16(1): pmaf033. https://doi.org/10.1093/jipm/pmaf033

Takekawa, Yukiko. 2010. The Use of Shellac, a Natural Resinous Substance: Focusing on Shōsōin Treasures and Medicinal Properties. Osaka Science Museum Research Report 20: 65-70. https://www.sci-museum.jp/wp-content/themes/scimuseum2021/pdf/study/research/2010/pb20_065-070.pdf

Takeo, N., Nakamura, M., Nakayama, S., Okamoto, O., Sugimoto, N., Sugiura, S., … & Matsunaga, K. 2018. Cochineal dye-induced immediate allergy: review of Japanese cases and proposed new diagnostic chart. Allergology International 67(4): 496-505. https://doi.org/10.1016/j.alit.2018.02.012

Toko, Yukiko & Komashiro, Motoko. 2007. Natural red dyes. Journal of Life Engineering Research 9(1): 136-139. http://hdl.handle.net/10083/3267

Watanabe, Hiroyuki. 2003. Scale insects save tropical forests. Tokai University Press, Hadano. 136pp. ISBN: 9784486016182

I originally have a science background, but I enjoy reading world history content.

I've heard something that caught my attention. It's the theory that spices (spices excluding the stems, leaves, and flowers) don't have much antibacterial property, and that "spices were used to mask the smell of rotten meat." I've always been skeptical about whether this is true.

Our investigation has concluded that this theory is highly unfounded. The reason is that spices are too expensive for ordinary people to use.

The medicinal properties of spices themselves are diverse, including antibacterial, antioxidant, appetite-stimulating, and anti-inflammatory effects. However, the reason why wealthy people in Europe and America sought out spices from abroad during the Age of Discovery was likely for their exotic flavors and because they stimulated the secretion of addictive neurotransmitters (brain hormones) in the brain.

Ultimately, this develops into conspicuous consumption among the wealthy in Europe and America (consumption to flaunt wealth).

However, it is becoming clear that some spices can actually be used to mask the characteristic fishy smell, so they are not spoiled, but it is true that some spices can be used to eliminate fishy odors.

Another theory suggests that the antibacterial and antioxidant properties of spices, which enhance their preservation, were important. This is an explanation that you sometimes see in high school world history classes.

While it is true that spices have antibacterial properties, it is unlikely that there was a demand for them in Europe and America during the Age of Discovery. On the other hand, antibacterial properties were likely important in their places of origin.

This article will explain why the idea that spices were used to mask the smell of rotten meat is false, and the real reason why European countries sought spices during the Age of Discovery.

What are the differences between Japanese pepper (Zanthoxylum piperitum), Chinese pepper (Zanthoxylum sibiricum), and Japanese pepper (Zanthoxylum ailanthoides)? We'll explain how to distinguish between similar species! What are their uses? What insects visit the flowers? Birds apparently love the seeds because they don't find them spicy!?

Japanese pepper (Zanthoxylum piperitum), Japanese sansho, and Japanese sansho are common species in Japan, and Japanese pepper in particular remains an essential ingredient in cooking today. All belong to the genus Zanthoxylum in the Rutaceae family, and are very similar in that they have many thorns all over the plant and odd-pinnately compound leaves consisting of an odd number of leaflets. Japanese pepper has a distinctive aroma...

ecological-information.com

What's the difference between dill (yin-dill) and fennel (foeniculum vulgare)? An explanation of how to distinguish between similar species.

Dill and fennel both belong to the Apiaceae family, share a strong aroma throughout the plant, and are used both as herbs (leaves) and spices (fruits). Their leaves, in particular, are known as "fish herbs" and pair exceptionally well with fish dishes. Furthermore, they are also similar in morphology...

ecological-information.com

Why can we say that the theory that spices were used to mask the smell of rotten meat during the Age of Discovery is false?

Why is the claim that "spices were used to mask the smell of rotten meat" considered to have little basis in fact?

The biggest problem is that spices from the Age of Discovery were too expensive (Murphy, 2024).

Europe already had an abundance of native herbs used in cooking, such as sage, rosemary, and thyme, as well as strongly flavored vegetables like leeks and onions. However, "spices" (such as pepper, nutmeg, and cloves) could only be imported through the spice trade from the Middle East and Asia.

Exotic spices, popularized by returning Crusaders and pilgrims, were already in vogue as highly prized luxuries among the upper classes in the Middle Ages, even before the Age of Discovery. However, their relative rarity, prestige, and the long distances it took to reach tables in France and England made them extremely expensive. They were simply unaffordable for ordinary households.

Furthermore, most households could quickly slaughter and eat animals by raising livestock or fish, hunting, or commissioning these activities. Examples of livestock included geese, ducks, chickens, pigs, and sheep.

In addition, if you have any leftovers, there are preservation methods such as salting, smoking, drying, and honey-preserving. Jerky and ham are examples of this.

From the above, it can be concluded that medieval Europeans did not deliberately eat rotten meat.

However, it has been confirmed that essential oils extracted from the fruit (fennel seeds) of fennel (a type of spice native to the Mediterranean coast) and the kernels of nutmeg seeds (native to Southeast Asia) can actually eliminate the odor of meat and fish (Takahashi et al., 2004).

Therefore, while it remains possible that native European plants like fennel were used to remove animal or fishy odors, it's unlikely to be the smell of rotting meat.

Why did the misinformation spread?

Why did this claim circulate? An influential book is involved (Myers, 2006).

In 1939, J.C. Drummond and Anne Wilbraham published "The Englishman's Food: Five Centuries of English Diet," in which they suggested that the wealthy in medieval Europe (and cunning bakers and grocery shop owners) desperately needed spices, primarily because meat was starting to spoil and the spices masked the smell and flavor of stale ingredients.

However, Drummond was a biochemist, not an expert in medieval food culture. Furthermore, he assumed from the outset that medieval preservation techniques were rudimentary and that "the main purpose of spices was to mask flavors." His work lacked documentary evidence and relied heavily on misinterpretations and speculation.

However, the readability of his writing, combined with the authority he gained from his social standing, gave his books weight and made them an ideal reference for anyone wanting to casually research the history of food.

This theory, like a rumor spreading, created a chain of mentions where inaccurate information was repeated as if it were the truth.

Worst of all, the speaker heard the same inaccurate information from multiple sources, but failed to realize that it all stemmed from a single source, creating the misconception that this theory was the dominant one.

What was the real reason Europe sought spices from abroad during the Age of Discovery?

So what was the reason for seeking spices during the Age of Discovery (mid-15th to mid-17th centuries)?

The primary reason is probably that it's a "delicacy" and has an exotic taste.

This might seem a bit simplistic, but the tendency for wealthy people to become gourmets in search of new flavors and seek out rare ingredients is still observed today.

If it were simply delicious, that would be the end of it, but for example, although it is native to Central and South America, the capsaicin contained in the fruit of the chili pepper is known to stimulate the secretion of beta-endorphins and dopamine, which are types of neurotransmitters (brain hormones) in the brain and are also called brain narcotics, due to its spiciness (pain) (Fattori et al., 2016).

This can have an effect that, while not pathological, could be described as addiction.

Other examples of spices affecting brain hormones, although primarily based on animal studies, include the following:

These effects likely contributed to a stronger craving for spices (Le Couteur & Burreson, 2003=2011).

As trade further developed and spices became even more expensive, the use of spices evolved into a way for the wealthy in Europe and America to flaunt their wealth and demonstrate that they could afford to use expensive spices on a daily basis (Freedman, 2005).

This corresponds to what is called "constancy consumption" in economics. This is not merely "showing off," but has been theorized in evolutionary biology as "handicap theory," and is known as an important motivation for consumption in humans (Miller, 2009=2017).

As described above, the reasons for seeking spices during the Age of Discovery likely evolved from the pursuit of delicacies to addiction and then to conspicuous consumption.

The reason Europe went to the trouble of obtaining spices by sea was that in the 15th century, the Ottoman Empire destroyed the Byzantine Empire and expanded into the Eastern Mediterranean, imposing extremely high tariffs. As a result, the supply of spices that had originally come in through the Eastern trade (Levant trade) between Islamic Qalimi merchants and Italian merchants in Venice was cut off.

As a result, the Portuguese and Spanish efforts to find spices unaffected by the Islamic world spread to the imperialist powers of the Netherlands, Britain, France, Germany, America, Italy, and Belgium, leading to colonial rule by Western powers around the world.

Is the antibacterial properties of spices related to the demand for spices?

However, and this is a bit complicated, while the reasons why Europeans and Americans sought spices during the Age of Discovery can be attributed to the pursuit of delicacies, their addictive nature, and their conspicuous consumption, the reasons why the indigenous people of those colonies used spices are likely different.

For the local people, unlike Westerners, spices grew naturally, were inexpensive, and were deeply integrated into their customs and food culture.

While taste and addictive properties are certainly contributing factors, the reasons for its long-term integration into the culture likely include its lipid-derived antioxidant, antibacterial, insecticidal, and animal-repellent properties, as well as its appetite-stimulating, anti-inflammatory, and odor-masking effects (Gottardi et al., 2016). Furthermore, although scientific proof is still lacking, it was also expected to play a role as a herbal medicine for specific organs.

In particular, antioxidant and antibacterial properties are thought to have been important for improving the preservation of food and for embalming corpses. Antibacterial properties have been proven in 99 major spices, including pepper, chili peppers, cloves, nutmeg, and sansho pepper.

Such antibacterial effects may not have been particularly valued in the European and American countries during the Age of Discovery.

However, as Dutch-Asian trade progressed from the 17th to the 18th centuries, and as a result of the expansion of trade and competition among merchants and companies, the prices of many commodities began to converge between regions. Colonial goods such as spices, tea, and sugar also spread to the general households in Europe and America (De Zwart, 2016), and became commonly consumed by ordinary households.

In Japan, after the Meiji Restoration (1853), spices originating from South America, such as chili peppers, were added to the existing Asian spices.

At this stage, some people may have started to become aware of its antibacterial properties and health benefits.

Since then, scientific research has advanced, proving that it actually has functions such as antibacterial properties and health benefits, and it has once again attracted attention.

Thus, the role of spices has changed in complex ways depending on the region and era. While the theory that spices were consumed for their odor-masking or antibacterial properties during the "Age of Discovery" is rather weak, it's important to note that spices themselves do have those effects.

References

Chauhan, S., Tiwari, A., Verma, A., Padhan, PK, Verma, S., & Gupta, PC 2024. Exploring the potential of saffron as a therapeutic agent in depression treatment: a comparative review. The Yale Journal of Biology and Medicine 97(3): 365-381. https://doi.org/10.59249/XURF4540

De Zwart, P. 2016. Globalization in the early modern era: new evidence from the Dutch-Asiatic trade, c. 1600–1800. The Journal of Economic History 76(2): 520-558. https://doi.org/10.1017/S0022050716000553

Fattori, V., Hohmann, MS, Rossaneis, AC, Pinho-Ribeiro, FA, & Verri Jr, WA 2016. Capsaicin: current understanding of its mechanisms and therapy of pain and other pre-clinical and clinical uses. Molecules 21(7): 844. https://doi.org/10.3390/molecules21070844

Freedman, P. 2005. Spices and late-medieval European ideas of scarcity and value. Speculum 80(4): 1209-1227. https://doi.org/10.1017/S0038713400001391, https://gebeasley.org/famished/wp-content/uploads/2015/10/document-2-1.pdf

Garabadu, D., Shah, A., Ahmad, A., Joshi, VB, Saxena, B., Palit, G., & Krishnamurthy, S. 2011. Eugenol as an anti-stress agent: modulation of hypothalamic-pituitary-adrenal axis and brain monoaminergic systems in a rat model of stress. Stress 14(2): 145-155. https://doi.org/10.3109/10253890.2010.521602

Gottardi, D., Bukvicki, D., Prasad, S., & Tyagi, AK 2016. Beneficial effects of spices in food preservation and safety. Frontiers in Microbiology 7: 186557. https://doi.org/10.3389/fmicb.2016.01394

Hidayat, R., Wulandari, P., & Reagan, M. 2022. The potential of cinnamon extract (Cinnamomum burmanii) as anti-insomnia medication through hypothalamus pituitary adrenal axis improvement in rats. Acta Medica Academica 51(2): 79-84. https://doi.org/10.5644/ama2006-124.375

Kim, CY, Seo, Y., Lee, C., Park, GH, & Jang, JH 2018. Neuroprotective effect and molecular mechanism of [6]-Gingerol against scopolamine-induced amnesia in C57BL/6 mice. Evidence-Based Complementary and Alternative Medicine 2018(1): 8941564. https://doi.org/10.1155/2018/8941564

Kulkarni, SK, & Dhir, A. 2010. An overview of curcumin in neurological disorders. Indian Journal of Pharmaceutical Sciences 72(2): 149-154. https://doi.org/10.4103/0250-474X.65012

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When you go to a yakiniku (Japanese barbecue) restaurant, you may come across four parts of the cow's stomach (fore-stomach) as a type of offal: mino, hachinosu, senmai, and giara.

Because it has a distinctive taste and is a type of offal, it's a love-it-or-hate-it kind of dish, but some people enjoy eating it because of its crunchy texture and how well it pairs with alcohol.

If you only eat them, you might not think much about their true nature or role, but they actually play an important role for ruminants, including cows.

This is essential knowledge for anyone involved in livestock farming, and it wouldn't hurt for the general public to know it as common sense.

However, the stomachs of ruminants have an overwhelming number of names, and I often find it difficult to understand the correspondence between their function and shape.

However, regardless of the sheer number of names, a closer examination reveals that the form, function, and order of these elements are highly logical and inevitable.

Here, I'll summarize some simple ways to remember the names and morphologies of the stomachs of ruminants.

To put it simply, the process is as follows: tripe (fermentation) → honeycomb tripe (separation) → omasum (absorption) → abomasum (digestion).

What is rumination? Why do animals ruminate and have a forestomach?

Rumination is the act of bringing grass that has been swallowed back into the mouth and chewing it again.

If you observe cows, you'll notice them constantly chewing for extended periods. This is because their stomachs are regurgitating food they've already swallowed, and they're chewing it again.

While this behavior may seem a little unpleasant to humans, it is an adaptation that gives herbivorous ruminants a significant advantage in grasslands.

The grass that is regurgitated does not simply return to the mouth as is. Ruminants have a stomach divided into four compartments, and the first stomach (the rumen) houses microorganisms, which ferment the grass they eat. Furthermore, the regurgitated grass is not exposed to stomach acid.

The plant cell walls containing polysaccharides such as cellulose and hemicellulose found in grass are extremely strong and normally only partially digestible by the digestive capabilities of ordinary animals. However, ruminants produce volatile fatty acids (VFAs, such as acetic acid, propionic acid, and butyric acid) through fermentation, which serve as a source of nutrition (Mackie, 2002; Bao et al., 2019).

However, microorganisms cannot properly ferment large pieces of grass. Therefore, ruminants repeatedly bring the grass back into their mouths, physically destroying it with their teeth and thus assisting microbial fermentation (Matsuda et al., 2011).

This allows them to efficiently obtain nutrients from even small amounts of grass, surpassing other mammals (Hofmann, 1989).

Furthermore, while microorganisms themselves synthesize proteins for their own use, ruminants send urea from their food and urea synthesized in their liver to their first stomach, allowing microorganisms to synthesize proteins, which the ruminants then swallow, making them their own proteins (Hailemariam et al., 2021).

Furthermore, it has been pointed out that stomach microorganisms can break down some plant secondary metabolites (phenols, alkaloids, etc.), which helps broaden their diet and increase their tolerance to toxicity (Loh et al., 2020).

While this may seem like a highly efficient function, it is a function completely specialized for herbivores. For frugivorous, carnivorous, or omnivorous animals, it lacks flexibility and is not cost-effective to maintain such a voluminous stomach (a trade-off). Therefore, humans and pigs do not have such stomachs.

What are the different types of ruminants?

Academically, "true ruminants" (Ruminantia), which have four stomachs (quadriventricular stomachs), refer to animals belonging to the suborder Ruminantia of the order Artiodactyla. The suborder Ruminantia is divided into two suborders, the infraorder Machodea and the infraorder Euruminantia, and six families, with approximately 200 extant species (Bao et al., 2019). The major families and representative examples are as follows:

• Bovidae: Includes genera such as cattle, sheep, goats, antelopes, and antelopes.
• Family Cervidae: Includes genera such as deer (Japanese deer), moose, and reindeer.
• Family Giraffidae: Giraffes and okapis.
• Pronghorn family (Antilocapridae): Pronghorn.
• Family Moschidae: Includes the genus *Musk deer*, etc.
• Family Tragulidae: Includes the genus Tragulidae, etc.

However, there are other animals that perform rumination (chewing the cud) and foregut fermentation, even though they do not have a four-chambered stomach. These animals have evolved convergently from different lineages and are therefore not usually considered "ruminants." Compared to ruminants, they have simpler stomachs and are less efficient at absorbing nutrients from grass.

The Camelidae family (camels, llamas, alpacas, etc.) belongs to the order Cetartiodactyla, but is part of the suborder Neopoda (cameloid suborder). They generally perform digestion that is "similar to rumination," but their stomach has three chambers and lacks the absorption function of the third stomach (lobular stomach) in ruminants (Fowler, 2008). They evolved separately from the ruminant suborder.

Although hippopotamuses belong to the order Cetartiodactyla, they are closely related to whales as they belong to the order Cetacea-Hippomorpha, and while they do not ruminate, they perform forestomach fermentation, which involves microbial fermentation in the forestomach (Clauss et al., 2004).

Many large marsupials (e.g., red kangaroos, large Australian macropods) perform foregum fermentation in the foregum, but do not engage in rumination in the usual sense (regular, repetitive re-chewing) (Vendl et al., 2017). However, there are individual records of regurgitation and re-chewing, which is called pseudo-rumination or merycism. Merycism is much shorter and less consistent than rumination, and is therefore often distinguished from rumination.

The proboscis monkey, Nasalis larvatus, also feeds on leaves and fruits and performs mericism and foregum fermentation (Matsuda et al., 2011).

The hoazin (Opisthocomus hoazin) is a bird, but it is a very unique example of a bird that performs strong microbial fermentation in an enlarged foregum (crop). Its chemical fermentation products (volatile fatty acids) and microbial communities are similar to those of mammals that ferment their foregums, but it does not ruminate (Grajal, 1995). It has been reported that it feeds its offspring substances that have been partially broken down and fermented from its food.

List of names and functions of the stomachs (fore-stomachs) of ruminants

Below is a table summarizing the naming of ruminant stomach parts based on their order, appearance, and their roles in relation to grilled meat.

It can be seen that fermentation, separation, absorption, and digestion occur from the first to the fourth stomach.

How do you remember the name and function of the first stomach (rumen, tumor, or stomach tumor)?

The first stomach is called a tumorous stomach in terms of its appearance, tripe in yakiniku (Japanese barbecue), and rumen in English.

The most distinctive feature of the first stomach is its significantly enlarged, lumpy appearance compared to the other stomach parts, which is why it is called a tumor stomach.

The name "mino" in yakiniku (Japanese barbecue) comes from the fact that when it's opened up, it resembles a "straw raincoat" (mino).

This morphology is closely related to the role of the first stomach.

The first stomach contains microorganisms (bacteria, protozoa, archaea, and fungi) that ferment cellulose and starch, producing volatile fatty acids (VFAs; acetic acid, propionic acid, and butyric acid). VFAs are the main energy source, and the microorganisms also supply proteins and vitamins (Perez et al., 2024). Lumen gas is expelled through movement (stirring) and belching (eructation).

In other words, it is thought that the first stomach is specially enlarged, like a "bump" or "skin," to expand the habitat for fermentation-promoting microorganisms.

Furthermore, numerous papillae develop on the inner surface of the rumen, increasing the surface area and aiding in VFA absorption (Pokhrel & Jiang, 2024).

The English word "rumen" is borrowed from the Latin word "rūmen." While there are several theories about its etymology, it is generally believed to originate from the Proto-Italic *roug(s)mən ~ *rug(s)mən < Proto-Indo-European *h₁rewg-, *h₁rewǵ- "to burp" (Wiktionary contributors, 2026).

This name also accurately describes the role of the rumen, where methane is mainly produced by the reduction of hydrogen (H₂) and methylated compounds by methanogenic archaea. This generates rumen gas, which mainly consists of carbon dioxide (CO₂) 45-75% and methane (CH₄) 20-35%, and ruminants expel this gas by belching (Zhang et al., 2020).

While burps containing methane from cows are sometimes considered a problem due to their role as greenhouse gases, this can be attributed to the rumen (first stomach).

The first stomach can be easily remembered if you think of it as a lumpy, cloven structure that houses microorganisms and is where unnecessary burps are produced.

As mentioned above, microorganisms also play a role in protein synthesis and detoxification of plant secondary metabolites (phenols, alkaloids, etc.).

How can you remember the name and function of the second stomach (reticulum, honeycomb tripe, or stomach cavity)?

The second stomach is called the reticulum in English, while the tripe is called honeycomb tripe in grilled meat.

The terms "reticulous stomach" and "honeycomb stomach" come from the fact that the mucous membrane of the stomach lining is arranged in a hexagonal, honeycomb-like pattern.

The English word "reticulum" is borrowed from the Latin word "rēticulum," meaning "net," and derives from the Latin word "rēte" ("net, snare") + -culum (diminutive suffix) < Proto-Italic *rēti- < Proto-Indo-European *h₁reh₁- meaning "separate, loose." It is cognate with the English word "reticle," which refers to the aiming line on a gun scope or microscope (Wiktionary contributors, 2026).

In other words, all of these originate from the fact that they have a polygonal, network-like structure.

This morphology is also deeply related to the role of the second stomach.

The second stomach contracts to separate small particles and the liquid phase and send them to the next passage, while sending back larger particles for rumination (re-chewing) (Song et al, 2024). The rumen and reticulum function in conjunction and are collectively called the "reticulorumen" or "ruminoreticulum."

During this sorting process, the multi-chambered spatial arrangement created by the pillars, which are sometimes called honeycomb or mesh-like structures, acts like a "shallow cage," controlling the flow rate and sorting efficiency.

In other words, larger particles remain inside the basket and are returned to the first stomach, while smaller particles and liquids flow to the third stomach and beyond. Conversely, digestive function is minimal.

Due to these characteristics, foreign objects such as metal can easily become lodged, which can lead to a disease called wound reticulogastroperitonitis (hardware disease), especially in cattle.

The second stomach is easier to remember if you think of it as an organ that sorts out food that needs to be ruminated, with a honeycomb-like network structure.

How do you remember the name and function of the third stomach (lobe stomach, omason)?

The third stomach is called "leaf stomach" in terms of its appearance, "senmai" in yakiniku (grilled meat), and "omason" in English.

The term "leaf stomach" comes from its structure, which consists of many layers of folds (thin, plate-like tissues) that resemble leaves or petals. The term "double-leaf stomach" is similar.

The name "senmai" is said to originate from its appearance, which looks like it has "a thousand" folds overlapping inside. There is also a theory that it comes from the Korean word "jeonyeob" (千葉/千枚), but the meaning is roughly the same.

In other words, they stem from almost the same characteristics.

This morphology is also deeply related to the role of the third stomach.

The third stomach absorbs water, electrolytes, and some VFAs, increasing the solid content ratio of the digested food before sending it to the fourth stomach. It can be said that it removes liquid and separates even finer particles (Pérez et al., 2023).

At this time, a large absorption surface is created by numerous leaves (laminae), enabling efficient absorption of water and VFAs.

The third stomach is easier to remember if you think of it as having countless leaf-like folds that appear to be thousands of leaves, and that it absorbs the liquid portion before the intestines.

The word omasum is a loanword from the Latin omāsum, meaning "bull's stomach." The Latin word is thought to be derived from Gaulish, which in turn was borrowed from Carthaginian, which in turn is thought to be derived from the Proto-Semitic *ḥamṯ- meaning "abdomen" (Wiktionary contributors, 2026).

The meaning of "Omason" has changed significantly from its original meaning.

How can you remember the name of the fourth stomach (abomasum, giara, or abomasum) and what is its function?

The fourth stomach is called "wrinkled stomach" based on its appearance, "giara" in the context of grilled meat, and "abomasum" in English.

The term "wrinkled stomach" comes from the fact that the mucous membrane has fine folds.

The term "true stomach" comes from the fact that it has the same function as the normal stomach of animals other than ruminants.

The fourth stomach is a "true stomach" with a glandular mucosa that secretes hydrochloric acid and pepsin, which acid-hydrolyze microbial and dietary proteins to prepare them for absorption in the small intestine (Ash, 1961). In this sense, it is "genuine."

Furthermore, the presence of wrinkles in the fourth stomach also has significance.

The folded folds in the stomach are folded when empty and unfold when full, increasing the gastric volume (variable volume). The folds also improve the efficiency of stomach wall movement (mixing and stirring), increasing the contact surface between acid and contents, thus facilitating digestion. These are not unique features and are consistent with the general function of the "rugae" of the stomach, including in humans.

Furthermore, the folding of the mucous membrane increases the surface area that accommodates the gastric glands, which secrete gastric juices such as hydrochloric acid and pepsin, allowing for more efficient secretion of acids, enzymes, and mucus.

Therefore, it's easier to remember that the fourth stomach is a "true stomach" with the same chemical digestion function for proteins as other mammals, and that it has gastric glands in its wrinkled folds that serve to temporarily store food.

Abomasum originates from the New Latin abomāsum < ab- "away from" + omāsum "bull's stomach." Therefore, it means "stomach away from the omason (third stomach)" (Wiktionary contributors, 2026).

As for the name "giara," a theory circulating on the internet suggests that it originated from "gibara," meaning "false stomach," because it functions like an intestine despite being the stomach.

However, it is the third stomach that functions like an intestine, while the fourth stomach is the stomach itself, as mentioned above, so this origin theory is not very convincing. It would be more understandable if it was confused with the third stomach, but there is no evidence to support that.

Another theory suggests that the name originated from "gyara" (gyaru) → "giara" (giara) because it was a payment (guarantee) received by people working at U.S. military bases (Tanabe, 2016), but the historical background is unclear, and this theory is also questionable.

References

Ash, RW 1961. Acid secretion by the abomasum and its relation to the flow of food material in the sheep. The Journal of Physiology 156(1): 93-111. https://doi.org/10.1113/jphysiol.1961.sp006660

Bao, W., Lei, C., & Wen, W. 2019. Genomic insights into ruminant evolution: from past to future prospects. Zoological Research 40(6): 476-487. https://doi.org/10.24272/j.issn.2095-8137.2019.061

Clauss, M., Schwarm, A., Ortmann, S., Alber, D., Flach, EJ, Kühne, R., … & Hofer, H. 2004. Intake, ingesta retention, particle size distribution and digestibility in the hippopotamidae. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 139(4): 449-459. https://doi.org/10.1016/j.cbpb.2004.10.002

Fowler, ME 2008. Camelids are not ruminants. In: ME Fowler, & RE Miller (Eds.), Zoo and Wild Animal Medicine (6th ed., pp. 375-385). Saunders. ISBN: 9781416057598, https://doi.org/10.1016/B978-141604047-7.50049-X

Grajal, A. 1995. Structure and function of the digestive tract of the hoatzin (Opisthocomus hoazin): a folivorous bird with foregut fermentation. The Auk 112(1): 20-28. https://doi.org/10.2307/4088763

Hailemariam, S., Zhao, S., He, Y., & Wang, J. 2021. Urea transport and hydrolysis in the rumen: a review. Animal Nutrition 7(4): 989-996. https://doi.org/10.1016/j.aninu.2021.07.002

Hofmann, RR 1989. Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system. Oecologia 78(4): 443-457. https://doi.org/10.1007/BF00378733

Loh, ZH, Ouwerkerk, D., Klieve, AV, Hungerford, NL, & Fletcher, MT 2020. Toxin degradation by rumen microorganisms: a review. Toxins 12(10): 664. https://doi.org/10.3390/toxins12100664

Mackie, RI 2002. Mutualistic fermentative digestion in the gastrointestinal tract: diversity and evolution. Integrative and Comparative Biology 42(2): 319-326. https://doi.org/10.1093/icb/42.2.319

Matsuda, I., Murai, T., Clauss, M., Yamada, T., Tuuga, A., Bernard, H., & Higashi, S. 2011. Regurgitation and remastication in the foregut-fermenting proboscis monkey (Nasalis larvatus). Biology Letters 7(5): 786-789. https://doi.org/10.1098/rsbl.2011.0197

Perez, HG, Stevenson, CK, Lourenco, JM, & Callaway, TR 2024. Understanding rumen microbiology: an overview. Encyclopedia 4(1): 148-157. https://doi.org/10.3390/encyclopedia4010013

Pérez, W., Duro, S., & Gündemir, O. 2023. Anatomical Differences in the Omasum of Weaning Calves Fed with Different Diets. Anatomia 2(2): 176-188. https://doi.org/10.3390/anatomia2020016

Pokhrel, B., & Jiang, H. 2024. Postnatal growth and development of the rumen: integrating physiological and molecular insights. Biology 13(4): 269. https://doi.org/10.3390/biology13040269

Song, Y., Lan,

Tanabe, Shintaro. 2016. On Beef. Poplar Publishing, Tokyo. 169pp. ISBN: 9784591152461

Vendl, C., Munn, A., Leggett, K., & Clauss, M. 2017. Merycism in western gray (Macropus fuliginosus) and red kangaroos (Macropus rufus). Mammalian Biology 86: 21-26. https://doi.org/10.2307/4088763

Wiktionary contributors. 2026, January 22. Wiktionary. https://en.wiktionary.org/wiki/Wiktionary:Main_Page

Zhang, Z., Wang, Y., Si, X., Cao, Z., Li, S., & Yang, H. 2020. Rumen methanogenesis, rumen fermentation, and microbial community response to nitroethane, 2-nitroethanol, and 2-nitro-1-propanol: an in vitro study. Animals 10(3): 479. https://doi.org/10.3390/ani10030479

Both Leptospermum scoparium and waxflower belong to the Myrtaceae family and are cultivated for ornamental purposes or used as branches in flower arrangements, as they are part of the "native flowers" or "wildflowers" collectively known as those native to Australia. Furthermore, some varieties of Leptospermum scoparium are known as nectar sources and are the raw material for Manuka honey. Some people may not be able to distinguish between the two species, but there are significant differences in the way the leaves are arranged and their shape. The flowers and fruits also differ, although this may be a little difficult to confirm. Manuka honey is certainly known to have antibacterial properties, but it does not have systemic effects, and its effects from the stomach to the small intestine are not yet well understood. This article will explain the classification and morphology of Leptospermum scoparium and waxflower.

What is Leptospermum scoparium (also known as wax flower)?

Leptospermum scoparium, also known as Manuka, Manuka Bush, Scoparium, Manuka Bush, or Nezumodoki, is a shrub or small tree native to southeastern Australia and New Zealand, and introduced to the United Kingdom (RBG Kew, 2025). In Japan, it is cultivated for ornamental purposes and used as a branch in ikebana (Japanese flower arrangement). Its name comes from the fact that its leaves resemble those of the Tamarix (Gyoryu) and its flowers resemble those of the Japanese plum (Ume).

The wax flower , Chamelaucium uncinatum, also known as Geraldton's wax flower, is a shrub native to western Australia and introduced to Britain and New Zealand. In Japan, it is cultivated as an ornamental plant and used as a branch in flower arrangements. Its name comes from the waxy, glossy appearance of its flowers.

Both belong to the Myrtaceae family and are cultivated for ornamental purposes or used as branches in flower arrangements as they are part of the "native flowers" or "wildflowers" collectively known as "Australia" (Sotooka & Funakoshi, 1991). Their unique shapes, which are not commonly found in Japan, give them an exotic feel.

Furthermore, in the case of Leptospermum scoparium, some varieties are nectar-producing plants, and the nectar collected from the flowers by European honeybees is known as Manuka honey. Manuka is the Maori word for Leptospermum scoparium itself. Few people may be aware of this.

Morphologically, both species are shrubs with linear, sharp leaves and five petals. They also share similarities such as a central depression in the flower containing nectaries and a nectar disc, surrounded by stamens arranged in a ring.

The petals come in various colors, but since they can range from white to red, they are often confused and difficult to distinguish.

What is the difference between Leptospermum scoparium and waxflower?

The differences between Leptospermum scoparium and waxflower are evident in various aspects (Flora of North America Editorial Committee, 2021).

As a fundamental point, Leptospermum scoparium belongs to the genus Leptospermum, while waxflower belongs to the genus Cameraucium.

Morphologically, the first difference is that the leaves of Leptospermum scoparium are alternate, while those of waxflower are opposite.

In other words, in Leptospermum scoparium, the leaves are arranged alternately on the stem, while in waxflower, they are arranged facing each other.

Furthermore, while both have long, narrow leaf blades with sharp tips, there is a difference: Leptospermum scoparium has broad, plate-like leaf blades, while waxflower has long, narrow, tubular leaf blades.

Regarding the flowers, there is a difference in that Leptospermum scoparium has no hairs on the style (the thin part below the stigma, which is the tip of the pistil), while waxflower has small hairs growing in a ring around the style just below the stigma.

If you carefully observe the pistil in the center of the flower, you'll notice that the differences are quite subtle.

In addition, Leptospermum scoparium has an ovary with 6 to 12 chambers and its fruit is a capsule that releases seeds when it dries, whereas waxflower has an ovary with 1 chamber and its fruit is nut-shaped, round, and remains hard even when dried. However, opportunities to observe this difference may be rare.

Does Manuka honey really have health benefits?

Manuka honey, made from the Leptospermum scoparium plant, contains methylglyoxal and other substances that provide antibacterial effects, and has recently become a very popular product due to its antibacterial properties and its prebiotic effect on regulating bowel function (Kato, 2019).

However, methylglyoxal itself is not present in the nectar of the Leptospermum scoparium flower; rather, its precursor, dihydroxyacetone, is present. Dihydroxyacetone, carried to the hive by bees along with the nectar, gradually transforms into methylglyoxal within the hive.

Leptospermum scoparium is becoming increasingly important in New Zealand, with serious efforts underway to cultivate and plant trees. Some researchers even predict that the area under cultivation for Manuka will reach 100,000 hectares in 10 years.

Does Manuka honey actually have any effect?

First, when used in the form of wound healing gauze or gel applied to the skin, its antibacterial activity is expected to protect against external infections while also accelerating healing.

On the other hand, if ingested orally, it may have an effect in the mouth, but methylglyoxal is almost entirely chemically digested and eliminated from the body, so it is incorrect to say that it "cures diseases throughout the body!"

The effects from the stomach to the small intestine are ambiguous. While it has been shown to kill H. pylori bacteria in the stomach in petri dishes, this has not been scientifically confirmed in the human body. Regarding the small intestine, there are conflicting results, with some showing no effect and others suggesting an effect on increasing beneficial bacteria.

However, since it certainly has antibacterial properties, there are undoubtedly situations where it can be used effectively, and it will likely continue to attract attention as an important plant in the future.

References

Flora of North America Editorial Committee. 2021. Flora of North America (Vol. 10 Magnoliophyta: Proteaceae to Elaeagnaceae). Oxford University Press, Oxford. 488pp. ISBN: 9780197576076

Kato, Yoji. 2019. Characteristics and functional properties of Manuka honey. Journal of the Japan Society of Home Economics 70(2): 97-101. https://doi.org/10.11428/jhej.70.97

RBG Kew. 2025. The International Plant Names Index and World Checklist of Vascular Plants. Plants of the World Online. http://www.ipni.org and https://powo.science.kew.org/

Sotooka, Shin and Funakoshi, Keiichi. 1991. A study on demand trends for branches and other edible plants. Research Report of Shizuoka Prefectural Agricultural Experiment Station 36: 11-16. https://agriknowledge.affrc.go.jp/RN/2010491099

Both Japanese anise (Illicium anisatum) and star anise (Illicium verum) belong to the genus Illicium in the family Schisandraceae. They are evergreen with glossy leaves, and their most distinctive feature is that their fruits are follicles, arranged radially in a cluster of eight. Both are considered very important plants both domestically and internationally, but their fruits are so similar that in Europe and America, Japanese anise is often mistaken for star anise. However, considering that Japanese anise is poisonous, while star anise is used as a spice and medicine, this mistake should not be overlooked. Japanese anise is found only in Japan and parts of the Korean Peninsula, while star anise is distributed in southern China and northern Vietnam, so when you see wild individuals in Japan, you can almost certainly assume they are Japanese anise. Morphologically, the biggest difference is the color and shape of the flowers, and the fruits also differ slightly in scent and shape. Because the components of the fruits are different, Japanese anise is used as a deterrent against animals at graves, while star anise is used as a spice and in medicines such as Tamiflu. Furthermore, the genus Illicium has very interesting ecological characteristics. This article will explain the classification, morphology, ecology, and uses of the genus Illicium.

What are Japanese star anise (Illicium anisatum) and Japanese star anise (Illicium verum)?

Illicium anisatum, also known as Shikimi, is an evergreen small tree distributed in Honshu (south of the southern Tohoku region), Shikoku, Kyushu, and the Ryukyu Islands in Japan, as well as the Korean Peninsula. It grows in mixed forests in mountainous and hilly areas, is used in Buddhist and Shinto rituals, and is often planted in temples and cemeteries (Kanagawa Prefecture Flora Survey Association, 2018). While the Japanese "Kanagawa Prefecture Flora 2018" and the British "Plants of the World Online" state that it is distributed in China and Taiwan (Kanagawa Prefecture Flora Survey Association, 2018; RBG Kew, 2025), this species is not listed in "Flora of China" (Wu et al., 2008).

Illicium verum, also known as star anise, is a small evergreen tree distributed in southern China and northern Vietnam, growing in forests and cultivated for medicinal purposes in southern China, southern India, and the Indochina Peninsula (Wu et al., 2008).

All of these species belong to the genus Illicium in the family Schisandraceae. They are evergreen with glossy leaves, and their perianth segments are narrow and linear-oblong.

[Seed Plant Encyclopedia #020] What are the species of Schisandraceae? Photo List

The Schisandraceae family consists of evergreen or deciduous woody plants, some of which are climbing. The leaves are simple, alternate, and lack stipules. Flowers are usually solitary in the leaf axils, lacking a clear distinction between sepals and petals, and the perianth segments are separate. The fruit is an aggregate fruit, consisting of berries clustered in a spherical or tufted arrangement, or a sac...

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Its most distinctive feature is that its fruit is a follicle, a compound fruit consisting of eight follicles arranged radially. While it is commonly sold and distributed under the name "star anise," this name derives from this characteristic.

Although both species are considered very important plants both domestically and internationally, they are extremely similar and often confused.

For example, if you do an image search on Google using the scientific name for star anise, " Illicium verum flower," almost all of the results will incorrectly show images of Japanese star anise (Illicium verum). It seems that in Europe and America, people mistakenly believe that Japanese star anise is star anise.

This misunderstanding is serious, and even Tomitaro Makino, the botanist who became the protagonist of the NHK serial drama "Ranman," pointed it out in his 1948 book. Apparently, even scholars in Europe and America continued to confuse the two at the time (Makino, 1948=2002).

However, considering that Japanese star anise (Illicium anisatum) is poisonous, while Japanese star anise (Penaeus chinensis) is used as a spice and medicine, this mistake should not be overlooked.

In fact, there have been numerous incidents where Japanese star anise (Illicium anisatum) has been mixed into the fruit or powder of Japanese star anise (Ginko et al., 2008; Cuenca et al., 2019).

What is the difference between Japanese star anise (Illicium anisatum) and Japanese star anise (Illicium verum)?

As a fundamental point, Japanese star anise (Illicium anisatum) is found only in Japan, while Japanese star anise (Illicium praecox) is found only on the Eurasian continent. Therefore, anything you observe in the wild in Japan is Japanese star anise.

However, it's true that distinguishing between Japanese star anise (Illicium anisatum) and Chinese star anise (Illicium verum) can be very difficult if you only focus on their morphology.

The most striking difference lies in the flowers (Mogi et al., 2000; Wu et al., 2008).

In Japanese star anise (Illicium anisatum), the flowers are 2-3 cm in diameter with 10-20 perianth segments and are yellowish-white, whereas in Japanese star anise (Hakkaku), the flowers are 0.8-1.2 cm in diameter with 7-12 perianth segments and are pink to dark red.

Morphologically, this is the most important difference; the other differences are quite subtle.

Regarding the fruits, a study by Chinese researchers states that Japanese star anise (Illicium anisatum) has a weak scent and taste, and its aggregate fruit can consist of more than eight fruits, while Japanese star anise (Star anise) has a distinctive scent and taste, and its aggregate fruit consists of eight fruits (Wang et al., 2018).

Furthermore, according to the Tokyo Metropolitan Institute of Public Health, the tips of each follicle in Japanese star anise are sharply pointed like needles and have a pungent scent similar to the incense used in Buddhist ceremonies, whereas the tips of each follicle in Japanese star anise are not sharply pointed but gradually become thinner and have a sweet scent (Tokyo Metropolitan Institute of Public Health, 2025).

However, scent is subjective, and the fact that the tip is sharply pointed is somewhat difficult to confirm, leading to the observation that they are almost indistinguishable (Cuenca et al., 2019). Distinguishing them may require some practice.

While the leaves appear almost indistinguishable, electron microscopy reveals a difference: the underside of the leaves of Japanese star anise (Illicium anisatum) is smooth, while that of Japanese star anise (Star jasmine) has many small grooves (Oh et al., 2003). It's possible that there might be a difference when touching them, but I haven't been able to verify that.

Star anise is often used in powder form, and sometimes Japanese star anise (Illicium anisatum) gets mixed in during this process. Chemical methods for distinguishing between the two to prevent this are being investigated, but we will omit the details here. For more information, please see Ginko et al. (2008).

What are the differences in how shikimi and hakkaku (Toshikimi) are used? One protects graves, the other protects lives!?

Both the fruits of Japanese star anise and Japanese star anise contain the compounds shikimic acid and anethole, but Japanese star anise contains only the toxic compound anisatin, which is a neurotoxin, while Japanese star anise does not contain anisatin, but instead contains compounds that are used as fragrances, such as estragole, and veranisatin A, B, and C (Cuenca et al., 2019).

For this reason, Japanese star anise is not edible for humans or cattle (Kobayashi et al., 2003), and there have been cases of poisoning. It is also believed that Japanese deer do not eat it (Kanagawa Prefecture Flora Survey Association, 2018). The etymology of the Japanese star anise is said to be "evil fruit."

However, this can also be used to mask the smell of death with its strong fragrance and to repel harmful animals. In Japan, it is widely used in Buddhist ceremonies (Hirano, 1997), offered before Buddha statues and graves, and the leaves and bark containing essential oils have been used as raw materials for incense powder and incense sticks.

On the other hand, star anise has been used as a spice in China since ancient times because its fruit is aromatic and contains antibacterial substances. Its use as food dates back to the Song Dynasty (960-1279 AD), and its use as medicine dates back to the Ming Dynasty (1368-1644 AD) (Zou et al, 2023).

In China, it is used in dishes such as Dongpo pork, Peking duck, and almond tofu, while in Japan, it is commonly used in braised pork belly. Braised pork belly is said to have originated from Dongpo pork.

Furthermore, one of the greatest benefits that star anise brings to humanity in modern times is that it is a raw material for shikimic acid, which is necessary for synthesizing oseltamivir phosphate, the main component of the antiviral drug oseltamivir that is effective against the influenza virus. Many people will recognize it if you mention the brand name "Tamiflu".

Because it can treat not only human influenza but also avian influenza, it has attracted attention as a groundbreaking drug.

Although research into the synthesis route of oseltamivir phosphate has progressed and methods for total synthesis have been developed, even now (2023), star anise is primarily used due to its ease of availability, abundant production volume, and economic advantages.

Around 2005, there were reports in Japan of two patients who died in accidents (such as falls) as a result of abnormal behavior, which may have left some people with a negative impression of oseltamivir. However, it is generally interpreted as a symptom of influenza itself, or that the risk is only slightly increased, and although there are restrictions on its use, it is still used today. Currently, it is not the only antiviral drug, and several similar antiviral drugs continue to be developed.

How is pollination occurring? Only gall midges were coming!?

Most species in the Schisandraceae family, including the genus Illicium, are thought to be pollinated and carried out by gall midges (Luo et al., 2018). However, this is different from the usual pollination method.

Generally, flowers of the Illicium genus open at night, emit a strong odor when fresh, and wilt after 2-3 days, sometimes 6 days. Illicium flowers are hermaphroditic, functioning as female flowers on the first night and male flowers on the following night.

It is known that the perianth segments do not fully unfold on the first night of flowering, gall midges lay their eggs in the flowers, and the hatched larvae form galls (insect galls) that feed on the flower's secretions (such as sesquiterpenes).

However, in some species of the genus Illicium, there are known instances where pollination occurs when the beetles are covered in pollen and come into contact with the stigma.

Furthermore, the gall midges that visit form a one-to-one correspondence, which is called "obligatory pollination symbiosis." In the case of the Japanese star-hornet, the visiting species is Resseliella spec. 16.

Unfortunately, we don't know much about Japanese shikimi (Japanese star anise) because it hasn't been studied or given much attention from this perspective.

It should be noted that the gall midge Illiciomyia yukawai, which creates galls on leaves, is a known species.

How do they disperse their seeds? They explode, are poisonous, yet edible!?

What role do the eight radially arranged aggregate fruits of the Illicium genus play in nature?

In fact, it has been discovered that it employs a unique seed dispersal method called ballochory (seed dispersal through the explosive splitting of the fruit) (Yoshikawa et al., 2018).

Specifically, when the fruit ripens, the seeds are exposed through cracks, and as the fruit dries, it explodes open and releases the seeds. This explosion can be seen in both fruit still on the tree and fruit that has fallen or been harvested.

This allows for a wider habitat range than simply relying on gravity dispersal.

However, research has shown that even with this method of seed dispersal, most seeds are captured in traps within 3 meters of the center of the parent plant, and only a very small number are captured in traps 6 meters away. It appears that seed dispersal by barocoria is not very effective at traveling long distances.

However, it has become clear that, at least in the case of Japanese star anise (Illicium anisatum), in addition to this, seed dispersal is also carried out by animal feeding.

It is quite surprising that this is happening with the poisonous Japanese star anise (Illicium anisatum). Most mammals, and even birds such as bulbuls, show no interest in Japanese star anise seeds, but two species of birds, the field mouse (a mammal) and the varied tit (a bird), have been confirmed to enjoy eating the fruit of the Japanese star anise.

It is thought that these two species neutralize the toxicity of anisatin for some reason, but the details are still unknown.

Amygdalin and capsaicin are well-known examples of substances that are toxic to mammals but non-toxic to birds. Plants sometimes select animals that eat their fruits, thus excluding animals that would eat their seeds or not carry them to a suitable environment. However, this case seems to be somewhat special.

Shikimic acid, anethole, estragole, and veranisatin A, B, and C may also have some effect on animals that eat fruit, but this is not well understood.

There's a difference between apricots and plums! What are the differences between plums, cherries, and Japanese apricots? We'll explain how to distinguish between similar species! Why do they bloom between plums and cherries? The fruit's toxicity didn't affect birds!?

Apricots and apricots are familiar foods because their fruits are often eaten as dried fruit. They are often treated as the same thing, and "apricot" is commonly used as the English name for "apricot." However, this is not always correct. Biologically, they are very closely related...

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References

Cuenca, MC, Agrasot, M. Á. C., Pegueroles, CM, & Cantó, VE 2019. New cases of star anise poisoning: Are we providing enough information?. Neurologia 34(3): 211-213. http://doi.org/10.1016/j.nrleng.2019.02.003

Ginko, E., Ölzant, S., & Länger, R. 2008. Illicium verum Hook. f. and Illicium anisatum L.: Anatomical Characters and their Value for Differentiation. Scientia Pharmaceutica 76(1): 65-76. https://doi.org/10.3797/scipharm.0802-03

Hirano, Takahisa. 1997. Tree Guidebook: Understanding the Characteristics and Uses of Trees Found in Gardens, Parks, and Wildlife. Nagaoka Shoten, Tokyo. 319pp. ISBN: 9784522215579

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Kobayashi, H., Kubota, Y., Yamada, H., Yasumoto, T., Okita, M., Hirata, H., … & Toyoda, Y. 2003. Shikimi poisoning in Japanese Black breeding cattle. Journal of the Japan Veterinary Medical Association 56(1): 15-20. https://doi.org/10.12935/jvma1951.56.15

Luo, SX, Zhang, LJ, Yuan, S., Ma, ZH, Zhang, DX, & Renner, SS 2018. The largest early-diverging angiosperm family is mostly pollinated by ovipositing insects and so are most surviving lineages of early angiosperms. Proceedings of the Royal Society B: Biological Sciences 285(1870): 20172365. https://doi.org/10.1098/rspb.2017.2365

Makino, Tomitaro. 1948=2002. Makino's Essays on Botanical Plants. Kodansha, 211pp. Tokyo. ISBN: 9784061595439

Mogi, T., Ishii, H., Sakio, H., Katsuyama, T., Ota, K., Takahashi, H., Shirokawa, S., and Nakagawa, S. 2000. Flowers Blooming on Trees: Polypetalous Flowers (Vol. 1, Revised 3rd Edition). Yama-kei Publishers, Tokyo. 719pp. ISBN: 9784635070034

Oh, IC, Denk, T., & Friis, EM 2003. Evolution of Illicium (Illiciaceae): mapping morphological characters on the molecular tree. Plant Systematics and Evolution 240: 175-209. https://doi.org/10.1007/s00606-003-0022-1

RBG Kew. 2025. The International Plant Names Index and World Checklist of Vascular Plants. Plants of the World Online. http://www.ipni.org and https://powo.science.kew.org/

Tokyo Metropolitan Institute of Public Health. 2025. How to distinguish between poisonous plants that are easily mistaken for edible wild plants: Illicium anisatum and Illicium erythrorhizon. Tokyo Metropolitan Medicinal Plant Garden. Pharmaceutical Research Department page. Tokyo Metropolitan Institute of Public Health website. https://www.tmiph.metro.tokyo.lg.jp/lb_iyaku/plant/yudoku-top/sikimi/

Wang, JL, Hu, MB, Wei, ZQ, Fan, WX, Liu, YJ, Wu, CJ, & Li, L. 2018. A novel strategy for rapid identification of the fruits of Illicium verum and Illicium anisatum using electronic nose and tongue technology. Tropical Journal of Pharmaceutical Research 17(4): 675-680. http://doi.org/10.4314/tjpr.v17i4.16

Wu, X., Raven, PH, & Hong, D. (Eds.). 2008. Flora of China (Vol. 7 Menispermaceae through Capparaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis. xii, 499pp. ISBN: 9781930723818

Yoshikawa, T., Masaki, T., Motooka, M., Hino, D., & Ueda, K. 2018. Highly toxic seeds of the Japanese star anise Illicium anisatum are dispersed by a seed-caching bird and a rodent. Ecological Research 33: 495-504. https://doi.org/10.1007/s11284-018-1564-6

Zou, Q., Huang, Y., Zhang, W., Lu, C., & Yuan, J. 2023. A comprehensive review of the pharmacology, chemistry, traditional uses and quality control of star anise (Illicium verum Hook. F.): An aromatic medicinal plant. Molecules 28(21): 7378. https://doi.org/10.3390/molecules28217378

Pyracantha coccinea, Pyracantha japonica, and Pyracantha leucocephala are all members of the genus Pyracantha in the family Rosaceae. They are characterized by their bright red fruits that appear in winter and are frequently cultivated as ornamental plants. However, in horticulture, these plants are often collectively called "Pyracantha" or "Pyracantha" without much distinction between the species, perhaps because they are difficult to distinguish. In reality, they are different species, and Pyracantha leucocephala can be easily distinguished by the hairs on the underside of its leaves and the color of its fruit. The problem lies in distinguishing between Pyracantha coccinea and Pyracantha japonica. There are differences in leaf shape, but it is quite complicated and a source of confusion. I strongly recommend observing the condition of the hairs on the flowers and the shape of the fruit instead. Pyracantha is sometimes said to be a cause of sudden death in waxwings, but I disagree. This article will explain the classification, morphology, and ecology of the genus Pyracantha.

What are *Pyracantha coccinea*, *Viburnum plicatum*, and *Pyracantha coccinea*?

Pyracantha coccinea, also known as evergreen hawthorn, is native to the Mediterranean region of Europe and West Asia, and is cultivated as an ornamental plant worldwide, including in Japan (RBG Kew, 2024). It was introduced to Japan during the Meiji era.

Pyracantha crenulata, also known as Himalayan craneberry, is an evergreen shrub native to Central Asia and China, and cultivated for ornamental purposes worldwide, including in Japan. It is believed to have been introduced to Japan in the early Showa period (1926-1989).

Pyracantha angustifolia, also known as false orange tree (Tachibanamodoki), is an evergreen shrub native to southern China and cultivated for ornamental purposes worldwide, including in Japan. It was introduced to Japan during the Meiji era.

All of these plants belong to the genus Pyracantha in the family Rosaceae, and in horticulture, they are collectively called "Pyracantha" or "Pyracantha" based on the genus name, without much distinction between the different species. They are very popular as ornamental plants and are frequently seen in urban areas. It is also common to see them growing semi-wild after their fruits are eaten by birds, and although they are an introduced species, they have become quite familiar in Japan.

The most distinctive features of these three species are their glossy, small leaves typical of evergreen trees, the numerous small, reddish fruits they bear, and the thorns growing from their branches. However, these characteristics are common to all three species, so it can be quite difficult to distinguish between them.

What are the differences between Hawthorn, Viburnum plicatum, and False Mandarin?

Of the three species, *Tachibana-modoki* can be distinguished relatively easily (Flora of North America Editorial Committee, 2015; Kanagawa Prefecture Flora Survey Association, 2018; Hayashi, 2019).

In contrast to Pyracantha coccinea and Pyracantha japonica, the leaves are somewhat wide, the underside of the leaves is hairless, and the fruit ripens to a bright red color, while in Pyracantha coccinea, the leaves are narrowly oblong to narrowly obovate, the underside of the leaves is densely covered with downy hairs, and the fruit ripens to an orange-yellow color.

The problem lies in distinguishing between *Pyracantha coccinea* and *Pyracantha japonica*. Distinguishing between these two species is quite difficult. There is inconsistency in how they are described in field guides, leading to confusion regarding their distinction.

A commonly cited difference is that the leaves of Pyracantha coccinea are oblanceolate or obovate, while those of Pyracantha coccinea are oblong or narrowly oblanceolate.

To put it simply, in the case of Pyracantha coccinea, the widest part of the leaf is towards the tip, whereas in the case of Viburnum plicatum, the widest part of the leaf is towards the center.

This point may also be helpful, but I think it's not very reliable because the explanations are very difficult to understand due to the use of technical terms, and there is too much variation from leaf to leaf and from individual to individual.

Personally, I think we should focus on checking the following two points.

Regarding the flowers, *Pyracantha coccinea* has fine hairs on the pedicel and calyx tube, while *Pyracantha japonica* has hairless pedicels and calyx tubes. To confirm this, you will need to record the back of the flower, so be careful.

Regarding the fruit, the fruit of *Pyracantha coccinea* is spherical, while that of *Pyracantha japonica* is oblate (a shape that looks like a sphere has been pressed only at the top and bottom).

Some books suggest that hybridization is occurring, so there may be individuals that are not clearly distinguishable, but the above method of distinction should be sufficient for now.

The difference in seed length—about 2mm for *Pyracantha coccinea* and about 3mm for *Viburnum plicatum*—is often mentioned, but it's certainly not practical.

Is it a myth that pyracantha poison causes sudden death in waxwings?

You often see descriptions in university-level textbooks and other sources stating that pyracantha fruit is a cause of sudden death in waxwings (Bohemian waxwings and Japanese waxwings). Pyracantha contains amygdalin, which is also found in some species of the rose family, such as apricots and almonds. When waxwings eat it, it is digested in their stomachs, and cyanide compounds are synthesized, leading to death due to the toxic components.

What are the differences between Bohemian waxwings and Japanese waxwings? What is their distribution? What are their summer and winter habits? What is the role of their crest feathers and red waxy substance? Can you tell their age from the waxy substance?!

The Bohemian Waxwing and the Japanese Waxwing are both brightly colored winter birds belonging to the Waxwing genus, possessing crests and often appearing in red or yellow. They are very similar, and it can be difficult to distinguish between them. However, checking the tips of their tail feathers will allow for reliable identification, and there are subtle differences in their coloration. Their distributions differ significantly; the Bohemian Waxwing...

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Is this really true?

Personally, I find this highly questionable.

This is because research in North America has shown that the closely related species, the Japanese waxwing, consumes large quantities of fruits containing amygdalin, such as the fruits of several species in the genus Prunus and several species in the genus Sambucus (Struempf et al., 1999).

Additional experiments have shown that when the Japanese waxwing ate artificial fruit containing four times the amount of amygdalin found in wild fruit, it did not exhibit any outward signs of toxicity such as tremors, ataxia, or paralysis, even after ingesting 5.5 times the oral lethal dose for rats in four hours.

Although the exact mechanism is not understood, it is thought that amygdalin is toxic only when ingested by mammals, or that mammals are resistant to cyanide compounds. In fact, it is believed that the presence of amygdalin in the fruits of the Rosaceae family is an evolutionary adaptation by the plants to ensure that only birds, which carry seeds over long distances, eat the fruit.

Therefore, it is unlikely that pyracantha would be the cause of death for waxwings without some other specific additional factor within Japan.

Upon reviewing the original study supporting this claim, the toxicity was confirmed by feeding mice pyracantha seeds collected from waxwing carcasses (Maruyama, 1998). Given the facts mentioned above, it cannot be said that this method yielded accurate results. The paper itself already mentions the possibility that mammals and birds have different toxin tolerances.

Another study has identified pesticide exposure, anemia due to overeating, and internal organ rupture or suffocation during falls as possible causes of sudden death (Miyagawa, 2007). Further research is needed to determine if these are the true causes.

References

Hayashi, Masayuki. 2019. Tree Leaves: Expanded and Revised Edition - Identifying 1300 Species Through Real-Life Scans. Yama-kei Publishers, Tokyo. 824pp. ISBN: 9784635070447

Flora of North America Editorial Committee. 2015. Flora of North America (Vol. 9 Magnoliophyta: Picramniaceae to Rosaceae). Oxford University Press, Oxford. 713pp. ISBN: 9780195340297

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Maruyama, Setsuko. 1998. On sudden mass death in migratory waxwings. Hygienic Chemistry 44(1): 17-24. https://doi.org/10.1248/jhs1956.44.17

Miyagawa, Ashiko. 2007. Investigation of the cause and process of the mass death of waxwings in Nagano Prefecture. Journal of the National Environmental Research Institute 32(4): 189-193. ISSN: 1346-4965, https://tenbou.nies.go.jp/science/institute/region/journal/JELA_3204025_2007.pdf

RBG Kew. 2024. The International Plant Names Index and World Checklist of Vascular Plants. Plants of the World Online. http://www.ipni.org and https://powo.science.kew.org/

Struempf, HG, Schondube, JE, & Del Rio, CM 1999. The cyanogenic glycoside amygdalin does not deter consumption of ripe fruit by cedar waxwings. The Auk 116(3): 749-758. https://doi.org/10.2307/4089335

Japanese madder (Akane), European madder (Akane serrata), and Indian madder (Akane umbellata) all belong to the genus Rubiaceae, and are well-known for their roots being used primarily for red dyeing. The color "akane-iro" (madder red) is derived from the plant "akane," and is also frequently used in personal names. Even though its use has declined, it remains a well-known Japanese word. However, few people may be familiar with the plant itself. Furthermore, while the three species mentioned above are generally known in the dyeing industry, descriptions often confuse them considerably. When distinguishing these three species, the number of leaves growing from a single point, the thorns on the stem, and the color of the flowers are important. Although all three are used for dyeing, their histories differ significantly. This is likely due in part to the significant differences in the chemical composition of the three species. Because of these differences in composition, the "akane-iro" of Japan is actually different from the "akane-iro" of other countries. This article will explain the classification, uses, and chemical composition of the genus Rubiaceae.

What are madder, European madder, and Indian madder?

Rubia argyi, also known as Japanese madder, is a climbing perennial herb distributed in Honshu, Shikoku, and Kyushu in Japan; as well as in Korea, Taiwan, and southern China, growing in forest edges and thickets (Kanagawa Prefecture Flora Survey Association, 2018). In Japan, it has been used for dyeing. Although its use has declined, it can still be commonly found in the wild.

Rubia tinctorum, also known as European madder, is a climbing perennial plant distributed in Europe and North Africa. It was cultivated for dyeing purposes throughout the world, mainly in West Asia, Central Asia, and South Asia, and has since escaped cultivation in various regions (RBG Kew, 2023). In Japan, the plant itself is rarely cultivated, mainly in botanical gardens.

Indian madder (Rubia manjith) is a climbing perennial plant distributed in southern China, Nepal, and India. It has been cultivated primarily for dyeing purposes, mainly in its native regions.

Both belong to the genus Rubia in the family Rubiaceae, and it is well known that their roots have been used primarily for dyeing red colors. In fact, European madder was used as a food additive in Japan until 2004. The color "akane-iro" (madder red) is derived from the plant "akane," and it is also a common personal name. Even though its use has declined, it remains a well-known Japanese word. The names of insects such as "akiakane" (autumn madder) and "natsuakane" (summer madder) are derived from the color, but these names would not have been given without akane.

What kind of dragonfly is a "red dragonfly"? Why does it turn red? Why does the common skimmer dragonfly turn blue? Two scientific reasons have been revealed. It turns out it's actually "sunscreen"!?

The "red dragonfly" is a creature so familiar to Japanese people that it even has its own children's song. The group commonly referred to as "red dragonfly" is a general term for dragonflies whose males turn red. Taxonomically, it's not a single group but rather a collective term for several separate groups, such as the Sympetrum and Scarlet Skimmer genera.

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However, few people may know about madder as a plant. The genus madder is characterized by its stipules, which are the same shape as the leaves, appearing as if 4 to 10 leaves are arranged in a whorl, its flowers are stalked, its corolla is 5-lobed, and its fruit is a siphon.

While the three types mentioned above are generally known in the dyeing and finishing industry, there is a considerable amount of confusion in their descriptions. In particular, what is actually madder is often referred to simply as "madder."

What are the differences between Japanese madder, European madder, and Indian madder?

Biologically, *Sympetrum frequens*, *Sympetrum parvulum*, and *Sympetrum indica* are completely different species (Wu et al., 2011).

As a fundamental premise, as mentioned above, the distribution differs in Japan, Europe, and South Asia, and originally, the types of dyes used varied depending on the region.

Morphologically, all members of the genus Sympetrum have leaves (more precisely, leaves and stipules) arranged in whorls, but while Sympetrum frequens and Sympetrum indica have four leaves in their whorls, Sympetrum parvifolium has six.

Furthermore, regarding the leaf veins, there is a difference between madder and Indian madder, which have palmate venation (veining that runs palmately from the base of the leaf), and European madder, which has pinnate venation (the typical venation composed of a main vein and lateral veins).

The difference between madder and Indian madder is that madder has downward-pointing thorns on its stem, while Indian madder does not.

Furthermore, regarding the flowers, there is a difference in that the flowers of *Rubia japonica* are white, while those of *Rubia nigricans* are red.

Based on the above, you should be able to distinguish between the three species as plants.

In addition, Japan has other species such as Rubia cordifolia var. lancifolia and Rubia hexaphylla, but both have leaves arranged in whorls of 6 to 8, and Rubia jesoensis can be distinguished from it by its upright growth rather than its climbing habit.

What are the differences in uses between the Japanese madder (Rubia japonica), European madder (Rubia nigrofasciata), and Indian madder (Rubia japonica)? Did they actually decline during the Heian period?!

Russula madder, Rubia verna, and Rubia tinctoria have all historically been used to extract pigment from their roots and dye cloth. The name "Akane" comes from the Japanese word for "red root." Its use seems to have developed independently in Japan, Europe, and India. However, nowadays, the use of these plants simply for dyeing cloth has declined.

Madder is one of the oldest red dyes used in Japan. It is already mentioned in written records in the Kojiki (compiled in 712), which was written during the Nara period (Gocho et al., 2023), but it is highly likely that it was used even earlier. Its color changes to various shades through chemical reactions; it becomes reddish-purple with lye mordant, scarlet with aluminum mordant, and red with the combined use of alkali and aluminum (Toko and Komashiro, 2007). During the Heian period, it was also used to dye armor and helmets, perhaps with the aim of boosting morale.

However, the madder dyeing technique was time-consuming and difficult, so it declined from around the late Heian period, and dyeing shifted to safflower (Carthamus tinctorius var. spinosus) and sappanwood (Biancaea sappan). In other words, the Japanese method of dyeing with madder has now become a "lost technology."

Rubia verniciflua has been cultivated as a dye in Central Asia and Egypt since ancient times, with records dating back to 1500 BC. Its use in the tomb of Pharaoh Tutankhamun is a particularly noteworthy example (Pfister, 1937). Records of its use in Europe are later, but the oldest known use is in textiles unearthed from the tomb of Merovingian queen Arnegundis in Paris, dating from 565 to 570 AD. The British New Model Army (the army of the English Civil War) also used it.

When mixed with clay and treated with alum and ammonia, it becomes "madder lake." Japanese madder produced a crimson color, but the color dyed with European madder is called "garance."

As for madder, it was used for a long time, perhaps because its production method was simpler than that of madder, and it was cultivated until the 19th century. However, in 1869, a German chemist chemically synthesized alizarin, the main component of madder dye, and from 1871 onwards it began to be produced industrially, leading to a decline in the cultivation of madder.

Although alizarin has largely been replaced by quinacridone pigment, a more lightfast pigment developed by DuPont in 1958, it has now found a use in biochemical assays to quantitatively determine the presence or absence of calcification by osteogenic cells using colorimetric methods (Smith et al., 2018). In other words, the presence or absence of bone can be confirmed using alizarin. This can be considered an important application.

In Japan, the red pigment from madder was used as a food additive under the name "madder dye," but it was banned in 2004 due to suspected carcinogenicity.

Finally, regarding Indian madder, cotton dyed with madder has been unearthed from the ruins of Mohenjo-daro (3000 BC) in India, indicating its use since ancient times. It is known as "manjishtha" in Sanskrit and was used by monks to dye their clothes.

What are the differences in composition and color between Japanese madder, European madder, and Indian madder?

Are there differences in the pigment components extracted from madder, European madder, and Indian madder?

There is a significant difference between these two (Oshita & Sakamoto, 2014).

Madder contains purpurin and mundistin as its main components, and pseudopurpurin as a secondary component.

Rubia vernalis contains alizarin as its main component, and rubiadin and alizarin glycosides as secondary components.

Indoor madder contains alizarin and purpurin, and its main component is anthraquinone-based pigment.

Therefore, there are also differences in color.

In the case of madder and rufous-green madder, the fibers are dyed red, while in madder, they are dyed a yellowish-red.

Considering this, it's safe to say that while both Japanese madder red and Western garance are in the red family, they are distinct.

References

Hiromi Gocho, Midori Muta, Mai Tsukazaki, and Miyuki Shiobara. 2023. Dyeing Methods and Color Characteristics in the Heian Period. Annual Report of the Institute for Literary Studies, Women's University 42: 1-12. ISSN: 0910-0679, https://doi.org/10.34388/1157.00002449

Kanagawa Prefecture Flora Survey Association. 2018. Kanagawa Prefecture Flora 2018 (Electronic Edition). Kanagawa Prefecture Flora Survey Association, Odawara. 1803pp. ISBN: 9784991053726

Oshita, Koji & Sakamoto, Akane. 2014. A Study on the Dyeing Behavior of Madder Dye. Journal of Cultural Heritage Informatics, Kibi International University Center for Cultural Heritage Research Bulletin 11: 21-24. ISSN: 1349-1628, https://www1.kiui.jp/pc/bunkazai/kiyo11/04_oshita_pp21-24.pdf

Pfister, R. 1937. Les textiles du tombeau de Toutankhamon. Revue des Arts Asiatiques 11(4): 207-218. ISSN: 0995-7510, https://www.jstor.org/stable/43475067

RBG Kew. 2023. The International Plant Names Index and World Checklist of Vascular Plants. Plants of the World Online. http://www.ipni.org and https://powo.science.kew.org/

Smith, WL, Buck, CA, Ornay, GS, Davis, MP, Martin, RP, Gibson, SZ, & Girard, MG 2018. Improving vertebrate skeleton images: fluorescence and the non-permanent mounting of cleared-and-stained specimens. Copeia 106(3): 427-435. https://doi.org/10.1643/CG-18-047

Toko, Yukiko & Komashiro, Motoko. 2007. Natural red dyes. Journal of Life Engineering Research 9(1): 136-139. http://hdl.handle.net/10083/3267

Wu, ZY, Raven, PH, & Hong, DY (Eds.). 2011. Flora of China (Vol. 19 Cucurbitaceae through Valerianaceae, with Annonaceae and Berberidaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis. ISBN: 9781935641049