As an actual breeder of Giant Water Bug, I can tell you where they live! Giant Water Bug is a large aquatic insect. Giant Water Bug are found in rice paddies, ponds, and lakes, but not so much in fast-flowing rivers. Specifically, where does the Giant Water Bug live?

Species and ecology of Giant Water Bug

Giant water bugs are large aquatic insects, with the largest species measuring nearly 10 cm in length. 005 and 006 in the photo below are Giant Water Bug.

The 005 is a subfamily of Lethocerinae that grows to over 5 cm, and the 006 is a subfamily of Belostomatinae that grows to a few cm. What people are generally searching for as Giant Water Bug is the subfamily Lethocerinae.

This article mainly deals with the Giant Water Bug of the subfamily Lethocerinae, but for more information on the subfamily Belostomatinae, please see the following article.

2020/04/18コオイムシの飼育と卵！かわいいがすぐ増えるので大変なことに

Giant Water Bug is a hunter that ambushes in the water, catching and eating frogs and small fish with its large paws.

Where do Giant Water Bug live?

Giant Water Bugs live in rice paddies, ponds, and lakes, but not so much in fast-flowing rivers.

The number of Giant Water Bugs in Japan is so low that you have to look for them to find them. In order to find a place where Giant Water Bug live, it is best to look for a place that has the following conditions.

• Areas where Giant Water Bug have been recent sightings.
• Terrain that is not affected by pesticides, such as hills and valleys
• Areas where invasive alien species such as carp, largemouth bass, bullfrogs and crayfish have not entered.

Giant Water Bug is not found in areas deep enough to require waders. Giant Water Bug is found in marshes that are a few centimeters to 20 centimeters deep that can be accessed with boots.

The Giant Water Bug needs to be close to the surface to breathe through its breathing tube. So it doesn’t need to be deep.

Giant Water Bugs caught in their habitat.

Have any of you ever seen a Giant Water Bug? I see Giant Water Bugs every year in the field and also have them at home.Giant Water Bug in Japan is an endangered and protected species, but it is not subject to hobby breeding.

This video showing that keeping a Giant Water Bug and netting it are two completely different experiences.

Where there are Giant Water Bugs, there are also many other aquatic insects.

Giant Water Bug in Japan feeds on tadpoles as larvae and on frogs and small fish as adults.

2022/01/24Find wild Giant Water Bug in the field

Causes of Giant Water Bug Decline

Giant Water Bug is decreasing in many places. The causes of the decrease in Giant Water Bug are as follows.

• Habitat is lost due to development
• Invasion of invasive alien species
• Die by being attracted to a streetlight
• Die from pesticides such as herbicides

Habitat is lost due to development

Giant Water Bug is the pinnacle of the ecosystem and needs wetlands that are rich in small fish and frogs to feed on. When agricultural waterways are revetted with concrete, the number of small fish and frogs decreases due to the faster flow and the inability of fallen frogs to escape.

It is easy for us to imagine that the pond will be reclaimed and the habitat will be lost.

Invasion of invasive alien species

When invasive alien species such as a crayfish (crawfish, Procambarus clarkii) , bullfrog (Lithobates catesbeianus), carp (Cyprinus carpio) and largemouth bass (Micropterus salmoides) invade their habitats, many native species disappear.

For example, crayfish have spread throughout Japan and have become so familiar that plastic models are being made.Crayfish have the ability to alter the environment by cutting water plants. It is well known that many native species disappear from ponds where crayfish have invaded.

Die by being attracted to a streetlight

Giant Water Bug is called an “electric light bug” because it is attracted to light.Giant Water Bug has a tendency to actively fly and move between ponds during the breeding season.

Although Giant Water Bug does not have a body shape suitable for flying, it is attracted to light and cannot leave the light, so they die. In Japan, there have been several reports of Giant Water Bugs gathering in large numbers during the period when powerful streetlights were installed, wiping out local populations within a few years.

The ability of the Giant Water Bug to attract light is also used in Southeast Asia, where the Giant Water Bug is an insect food.

Die from pesticides such as herbicides

Giant Water Bug is known to be extremely sensitive to pesticides.

Giant Water Bug was common in Japan half a century ago, but has been declining nationwide and became a protected species in 2020. After World War II, the use of pesticides began, and by the 1980s, local extinctions of Giant Water Bug were reported in many places.

There are still areas in rural Southeast Asia where pesticides are not used, and there are so many Giant Water Bugs that they are edible.

Giant Water Bug is a fascinating species, but it is declining across the country, and we have fewer opportunities to see it up close. Let’s take a look at Giant Water Bug photos from different angles and enlarge them to see the details.

Giant Water Bug is found all over the world, but the one in this article is from Japan, scientifically named Kirkaldyia deyrolli. Kirkaldyia deyrolli is a largest aquatic insect in Japan, with a body length of nearly 7 cm.

Giant Water Bug has been a protected species in Japan since 2020, but hobby keeping is not regulated.

2022/01/24Find wild Giant Water Bug in the field

Photos of adult Giant Water Bug

In the photo below, the Giant Water Bug has a white cottony water mold on its proboscis. This is common in captivity, but does not seem to affect them to the point of death.

Most of the world’s Giant Water Bugs belong to Lethocerus. Japanese Giant Water Bug used to be classified as Lethocerus, but due to its large forelegs and long claws, it became independent as Kirkaldyia deyrolli.

Photos of mating and egg laying of Giant Water Bug

The Giant Water Bug is an ambush species and usually does not move much, but during the breeding season, it actively moves to find a mate.

Males of the Giant Water Bug call for females by pumping the surface of the water, leading to mating.

Mating of Giant Water Bug is carried out intermittently during spawning. Males mate many times, getting off and Mating in the Giant Water Bug is intermittent during spawning. The male mates repeatedly while climbing down and up the pole.

2020/12/19【写真・動画】タガメの卵！交尾・産卵の流れ

Giant Water Bug’s genitalia.I don’t know what’s going on.

Giant Water Bug lays its eggs in bubbles, which disappear some time after spawning. There seems to be another object that attaches the egg mass to the pile.

Giant Water Bug forms egg masses and lays its eggs from the top down.

In the photo below, one of the eggs is darker than the rest, and it looks like it’s sterile.Not all Giant Water Bug eggs hatch.Sometimes the hatch rate is as low as 50-70%.

Egg mass destruction by a female Giant Water Bug

The destruction of egg masses by female Giant Water Bugs is a frequent occurrence in captivity. Unless the egg masses (and the males protecting them) are isolated, it is safe to say that they will be destroyed first.

The female attacking the egg mass and the males to protect fought and knocked down the struts. After that, the female In the photo below, a female turtle attacking an egg mass and a male protecting it fought and knocked over a post.

The female then sucks the eggs for sustenance, and the male also resists at first, but is often driven away by the larger size of the female.

Extra. A chaotic photo of a pair of Giant Water Bug laying eggs and another individual eating a loach.

Giant Water Bug sometimes feed on the water to prevent others from taking their food if the surroundings are noisy.During spawning, the male climbs up and down and makes a lot of noise, so I think this is what happened.

Photos of Giant Water Bug egg masses and their hatching.

It is well known that male Giant Water Bugs are protective of their egg masses, but they don’t stick around all the time. They may be found at the base of a support pole, and climb up when stimulated.

Even though they are aquatic insects, Giant Water Bug are not completely adapted to living in water, and lay their eggs on the water. They lay their eggs on the water, and if the eggs are not watered, they will dry up and not hatch. Water supply by the male or a human is the key to development.

Eggs of Giant Water Bug basically expand every day. A deflated egg is a damaged one.

Eggs of Giant Water Bug are green immediately after spawning, and then brownish streaks appear. These gradations appear because the eggs are laid in order from the top.

Giant Water Bug larvae do not always hatch in unison, although they are famous for their simultaneous hatching photos.

However, Giant Water Bug larvae do not always hatch at the same time. In captivity, they may hatch in different stages, depending on the lighting conditions. In this case, the hatching rate is often extremely low, such as less than half.

The hatched Giant Water Bug larvae fall into the water. Yellow one in the photo is just after birth. A few hours later, the striped pattern unique to the first instar larvae emerges.

Photos of Giant Water Bug larvae

The larvae of Giant Water Bug are characterized by a large variation in color and pattern from one stage to the next. In particular, the first instar larvae of Giant Water Bug are striped blackish-brown in color, which differs from the greenish body color of the second instar and later.

Giant Water Bug grows quickly and is capable of feeding on prey more than twice its length immediately after birth. It is also common to see multiple Giant Water Bug larvae attached to a rampaging prey.

The photo below shows the first instar larva of a turtle attacking a killifish. The belly is swollen.

One of the reasons why the first and second instar larvae are so prone to death is that some of them are born in groups of 50 or more, so they do not get enough food. Giant Water Bug larvae with floppy and thin abdomen are not getting enough food.

Immediately after molting, Giant Water Bug larvae glow emerald green, but after a while they return to a more subdued color.

Some books say that Giant Water Bug larvae are cannibalistic and should be kept individually, but young larvae can be kept in groups. They frequently overlap each other, and I have the impression that they do not actively cannibalize each other.

In the case of insufficient food, the young larvae simply die, and cannibalism tends to occur when they become about four or five years old.

The second instar larvae of the Giant Water Bug are gourd-shaped, but when they reach the third instar, their width increases.

Giant Water Bug larvae are larger and more numerous when they reach the third instar stage, so they fill up their rearing containers.

In the case of the Diving Beetle larva, the body segments grow longer, but in the case of the Giant Water Bug, as it grows, the upper and lower parts of the body become thicker and swell up like a water bottle before finally molting.

In the photo below, the pronotum is already cracked and the Giant Water Bug larva has begun to molt.

Key to success in the Giant Water Bug larval molt is the clean exit of the legs. The larvae that become defective due to the leg tips getting caught, for example, almost never survive.

Giant Water Bug has sharp claws on its front legs, but as a larva, it has two claws.

GGiant Water Bug larvae breathe by storing air in their abdominal cilia. In captivity, there are quite a few individuals that die from respiratory failure. It is also effective to use a filter to reduce the frequency of water changes.

Spiracles of the Giant Water Bug moves to the abdomen as a larva and to the back as an adult. Each black dot near the edge of the abdomen is a pneumatome.

Wings of Giant Water Bug do not increase in size with each larval stage, but suddenly and prominently protrude at the fifth stage.

Giant Water Bug’s diet consists of extracorporeal digestion, in which digestive juices are injected into the food to dissolve it. The mouth moves freely.

The 5-larva of Giant Water Bug changes reddish-brown with the approach of emergence.

The photo below is a female because it is large and wide.

Giant Water Bug larvae have a different body size when they reach the 5th instar stage, and it is possible to determine male and female.

Giant Water Bug hatching photo

It takes about 40 days after hatching for a Giant Water Bug to become an adult.I observed the Giant Water Bug 5th instar larvae hatching! It takes about 20 minutes for neoteny to be born.

2020/12/16タガメの羽化！黄金の新成虫は飼育のハイライト

The photo below shows a Giant Water Bug 5th instar larva with its back cracked and molting started.

The larva shakes its body and pulls out its upper body.

Wings grow in parallel with the molt.

Adult Giant Water Bug breathes by storing air between its back and wings. For this purpose, its back is densely covered with fine hairs.

Neoteny is pale in color for a while, but gradually becomes darker. The body remains soft for a few days.

In 2020, I found wild Giant Water Bug in several places, but where can I find the habitat of Giant Water Bug in Japan, and can even an amateur find them?The scientific name for the Japanese Giant Water Bug is Kirkaldyia deyrolli.

The Giant Water Bug is an interesting species in captivity, but I wanted to find one in the wild, learn about its actual habitat, and maybe even take some ecological photos!

I was in a hurry and couldn’t get a good shot, but I was happy to find a Giant Water Bug and see it preying on a frog.

The Giant Water Bug from Japan became a protected species in 2020, but it is not subject to regulation for individuals to raise it as a hobby.

Expedition to Giant Water Bug’s habitat

I have never thought of a collecting expedition because I don’t have a driver’s license. It would be too difficult to go to a distant wetland by train with a large luggage.

In 2020, a friend of mine invited me to go collecting, and I went looking for Giant Water Bug several times.

As a result, I found a Giant Water Bug on the second trip, and on the third trip, I asked my wife to drive us to a different location and found a Giant Water Bug.

Therefore, the level of difficulty in collecting Giant Water Bug in the Kanto region of Japan is such that a knowledgeable person can find it even if they start from scratch.

Aquatic Insects in the Year 2020

Looking for the Giant Water Bug resulted in finding other aquatic insects as well. Here are a few photos.

An approach to finding a habitat for Giant Water Bug

If you were trying to find the habitat of the Giant Water Bug from scratch, what would be the best way to do it?

Ask someone to pinpoint the Giant Water Bug’s habitat

The easiest way is to ask someone to pinpoint the habitat of the Giant Water Bug. However, this is not interesting because it is a matter of course that wherever they are, they are.

I have had people tell me where to find Giant Water Bug, but it is important to have the experience of finding the habitat of Giant Water Bug by yourself based on a hypothesis.

Narrow down the approximate habitat area from past records.

If I were to be too specific, it would identify the habitat, so I will be blunt. For example, if I write about XX prefecture, it is too wide and I can’t consider the habitat. If it’s not in your hometown, you will have to narrow it down to the city level because of the travel time to get there.

From past records and information about seeing Giant Water Bugs on Twitter, we can usually tell which areas have been confirmed to be inhabited by them even in the recent past.

For example, the Giant Water Bug is widespread and thinly distributed in the northern Kanto region of Japan. They fly several kilometers during the breeding season, so there is no reason to go there just because you happen to find one in the city.

What should I do to narrow down a few more candidates?

Consider the habitat requirements of the Giant Water Bug.

If we work backwards from the causes of the Giant Water Bug’s decline, we can see where they are still breeding today.

The Giant Water Bug is the apex of the ecosystem and is extremely vulnerable to pesticides. Therefore, a place where aquatic insects, which are in the lower part of the ecosystem, are also abundant and free from pesticides is a good candidate.

Specifically, the place where the pesticides of the fields flow downstream and crayfish and bullfrogs have invaded and become dead colored water without water plants is unlikely.

If there are enough small shrimps, loaches, or some aquatic insects in the net each time, the expectation of finding a Giant Water Bug will increase.

On the other hand, if the net is filled with crayfish every time, or if we hear the croaking of bullfrogs, we will sigh and retreat.

In terms of probability, Giant Water Bug is not found in fast flowing or deep water, because its larvae are not very good swimmers.

Giant Water Bugs are more likely to be found in waterways next to rice fields and unbanked waterways up to 20cm deep. Concrete waterway with fast flowing water are unlikely to have Giant Water Bugs, and even if there are Giant Water Bugs, it is probably just a coincidence that they have been swept away.

TThe photo shows a place where there is supposed to be a nice waterway, but it has just been renovated. There were still some small Water Beetles swimming around in the surrounding puddles, so the Giant Water Bug was unlikely.

What is “Yatsuda”? Rice paddies in the valley.

There is a topography called “Yatsuda” as a habitat for Giant Water Bug that meet these conditions. Yatsuda is a paddy field environment using “Yato”.

Yato is a valley-like topography formed by the erosion of hills. Both sides are hilly, and rice fields spread between them, and there are reservoirs and thin water flows upstream.

Although the impact of pesticides is limited in such topography, it is difficult to modernize, it is easy to become fallow fields or abandoned, and it is easy to become land.

How to view and manage potential sites in Google Maps

I was going to write about how to preview collection spots in Google Maps and how to manage candidate sites in Google Maps, but it would be too long, so I’ll write about it in another article.

2020/12/06ストリートビューで下見したり、Google Mapsで採集スポットを管理する技術

We are unable tPlease note that I cannot answer questions like “Please tell me the habitat of Giant Water Bug” from strangers. I can’t answer questions like that. We’ll get to know each other better and then we’ll go collecting and observing together.

It is a report that overturns the perception that Giant Water Bug prey on small fish and frogs.A record of a frog predation by Lethocerus patruelis, the only Giant Water Bug in Europe, has been published.The Giant Water Bug in Europe seems to eat very few frogs.

* The picture at the beginning is a Japanese Giant Water Bug, not a European Giant Water Bug.

A records of the Giant Water Bug (Lethocerus patruelis) inhabiting The Balkans preying on the frog Pelophylax kurtmuelleri have been published

Giant Water Bug is a predator that catch vertebrates such as fish, turtles, snakes and frogs with their large forelegs. The genus Lethocerus often preys on frogs, but no such cases have been confirmed in Europe (surprising!).

In this case, an adult Giant Water Bug (Lethocerus patruelis) preyed on frogs was recorded during a frog survey in a rice field in central Greece in August 2021. The temperature is 33 degrees celsius and the water temperature is 23.5 degrees, and the climate is close to summer in Japan.

Reference:Predation of the Balkan frogPelophylax kurtmuelleri (Gayda, 1940) (Anura: Ranidae) by the giant water bug Lethocerus patruelis(Stål, 1854) (Heteroptera: Belostomatidae)

World Giant Water Bugs and European Giant Water Bugs

The family Heteroptera: Belostomatidae is a carnivorous aquatic beetle, including the world’s largest aquatic insect. Among them, the Giant Water Bug subfamily (subfamily Lethocerinae) is divided into three generas, Benacus and Kirkaldyi and Lethocerus, which are known to prefer vertebrates as bait at each stage of growth. Specifically, in addition to larvae of fish and amphibians, records of preying on turtles and snakes are also recorded.

2021/07/16ヘビ・カメ・鯉も！タガメが捕食した巨大生物の記録

The genus southeast asian Giant Water Bug (Genus Lethocerus) is divided into 22 species, many of which live in the tropics, subtropical and temperate zones. Lethocerus patruelis, the only Giant Water Bug living in Europe, is the largest aquatic insect in Europe.

Lethocerus patruelis live mainly in the Balkans (Albania, Bosnia, Bulgaria, Croatia, Montenegro, Romania, and Serbia) and have recently been reported from Italy. Lethocerus patruelis is found throughout Greece and often in estuarine deltas and areas with slow currents.

Many species of Giant Water Bug are distributed in the Americas, as there are only one species in Europe and only two species in Asia: Japanese Giant Water Bug (Kirkaldyia deyrolli) and Taiwang Giant Water Bug (Lethocerus indicus).

2021/03/28食用に販売される“タイワンタガメ”の味や特徴

2021/01/24世界にはどんなタガメがいる？ナンベイオオタガメは最大何cm？

European Giant Water Bug (Features of Lethocerus patruelis)

Summary so far. The fact that this is the first record seems to indicate that the European Giant Water Bug does not eat frogs as its main food source.

Lethocerus patruelis looks like it has features common in the genus Lethocerus, with a body length of 6-7 cm for males and 7-8 cm for females, almost the same physique as The Lethocerus indicus, which has a large population in Southeast Asia.

The distribution of Lethocerus patruelis is wide from the Balkans to India and Myanmar. According to the example of a Bulgarian study, it seems to be attracting attention that it is moving northward from the Balkans recently.

According to the observation records of Lethocerus patruelis in iNaturalist, it seems to inhabit mainly the southern coast of the Balkan Peninsula.

Water bugs such as dragonflies and water Ranatra chinensis are sometimes parasitized by water mites. When they are parasitic, they are bag-shaped and immobile, so I kept them for a while to check where the adult mites started swimming.I have to admit, I was surprised by water mite.

Water mites are brightly colored and are called jewels of the waterfront

There are more than 200 species of mites in Japan alone, and their body color is so vivid that some of them are named after jewels. I’ve encountered them relatively often in the field, but I’ve always just passed them off as “Oh, those things. The other day, the topic of mites came up in a conversation with a follower, so I decided to take a closer look.

The body color is beautiful, and there are a lot of beautiful one such as red, orange, green, and yellow, and there is the one named hosek mite and ruby mite. Since there are many things within 1 mm in size, it is too small to observe with the naked eye, so researchers and enthusiasts of aquatic insects are few people who seriously look at mizudani even if they know it.

Proposal of environmental learning program utilizing plants in Fukada Park

Water mites are parasites of a wide range of aquatic insects.

Water mites look like ordinary mites, but they live in water and parasitize aquatic insects. According to a paper summarizing the parasites (Dr. Ohba again!) ) that summarizes the parasites, there are records of parasites on mosquitoes, woodpeckers, giant water bugs, water squirrels, dragonflies, gadflies, snails, and bivalves.

Masuda (1942) reported parasitizing on Appasus japonicus and Ranatra chinensis in Osaka City. Abé et also al. (2015) reports that a species of the genus Ozumidani collected in Sagamihara City, Hiratsuka City, Minamiashigara City, Minamiashigara City in Kanagawa Prefecture, and Hokuto City and Nirasaki City in Yamanashi Prefecture and Mizukamisani collected in Tatsuno City and Sayo Town, Hyogo Prefecture are infested with a species of plums, that there is a preference for the species of aquatic insects that are the host, that there is a tendency for more mites to live in larvae than adults in the Appasus japonicus, there is no difference in the paragenic rate in relation to the difference in male males and body sizes of Ranatra chinensis. tends to parasitize mites on the chest and legs.

Earth mites parasitic on Japanese aquatic animals

As far as I can tell, there seems to be a difference in the parasite rate of mites between the praying mantis and the flying squirrel. While the praying mantis is often attached to the ground, I don’t see it as often in the white stork. I wonder if the difference is that they hide in the mud.

“That bag” attached to aquatic insects is a parasitic form of a water mite

The water mite parasitizes in the bag form like this, and in the photo below more than 10 individuals parasitize.

The life cycle of the water mite follows the developmental process of egg, egg pupa, larva, first pupa, young, second pupa, and adult. When the larvae are parasitized, they become the first pupae, and when the young are parasitized, they become the second pupae. The young and adult pupae are free-swimming, while the pupae are pouch-shaped and immobile. We often see the second pupa, which is the large and conspicuous one.

I don’t know why there are two stages of pupae, but it may be because of the need to switch when the parasite molts or hatches.

Incidentally, a newt parasitic mite has also been found (press release), , and since this member of the family spends its entire life on the body surface of newts, the presence or absence of molting and hatching may have affected the evolution of the growth process.

Adult water mites swims skillfully

The parasitic mite is baggy and immobile, so I wondered if it was a mite. I would like to see the adult mites. After keeping Ranatra chinensis for a while, an adult mite appeared, so I collected it with a dropper and took a video.

They are 1-2mm in size, so you can’t see the details, but you can see how they move their legs and swim skillfully. The vivid red color also makes it an eye-catching creature.

If you are searching for “giant water bug type” you are probably looking for the type of giant water bug used in insect eating or the type of insect you caught. Giant water bug is largely divided into the subfamily Lethocerinae and the subfamily Belostomatinae.

There are two types of Giant Water Bug found in Japan.

There are two types of Giant Water Bug that the general public has the opportunity to see: wild Giant Water Bug or Taiwanese Giant Water Bug = Lethocerus indicus imported from Southeast Asia as insect food. In Japan, the subfamily Belostomatinae is treated independently of the Giant Water Bug.

Compared to overseas Giant Water Bug, Japanese Kirkaldyia deyrolli have a large forefoot in physique ratio, and the difference from Lethocerus indicus is clear because of its appearance features such as a triangular eyeball. The body length is about 10 mm larger for Lethocerus indicus with a maximum body length of less than 70 mm.

Japanese Kirkaldyia deyrolli are an endangered species protected by law, but Lethocerus indicus are not regulated. For the time being, the Giant Water Bug with an inverted V-shaped pattern from the head to the chest is Lethocerus indicus. If you remember this much, you’re fine.

2021/01/24世界にはどんなタガメがいる？ナンベイオオタガメは最大何cm？

2020/02/10【FAQ】販売・飼育禁止？！タガメの規制で何が許され何が禁止されるか？

A type of insect similar to a Giant Water Bug

IIf you are not familiar with insects or have never seen the subfamily Lethocerinae, you may mistake the subfamily Belostomatinae for the subfamily Lethocerinae. The species that fly into lights can surprise you by being in unexpected places.

The following photos are insect specimens from the National Museum of Nature and Science in Ueno, Japan: 005 is Lethocerus indicus, 006 is Appasus major, and 007 is water scorpion. It is regrettable that the major species in Japan are not lined up with each other, but it is a good reference for the body size ratio of each species.

Japanese large hemipterous aquatic insects are divided into the families Belostomatidae and Nepidae. The other species are smaller and less common.

IIf you are interested, the book “Aquatic Insects of Japan,” which lists all the aquatic insect species in Japan at the present time, is useful.

日本の水生昆虫 (ネイチャーガイド)

created by Rinker

文一総合出版

¥5,500(2025/08/07 22:14:01時点 Amazon調べ-詳細)

• Amazon
• 楽天市場

Subfamily Belostomatinae carrying eggs on the back

The subfamily Belostomatinae, which is a smaller version of the subfamily Lethocerinae, is the aquatic insect that is most easily mistaken for the subfamily Lethocerinae.

The subfamily Belostomatinae is the most easily mistaken for the subfamily Lethocerinae. It is easy to identify the subfamily Belostomatinae when it is carrying eggs, the subfamily Lethocerinae when it is 5-6 cm long, and the subfamily Belostomatinae when it is around 2 cm long.

2020/04/18コオイムシの飼育と卵！かわいいがすぐ増えるので大変なことに

You may be think “Are they small because they are children of the subfamily Lethocerinae?”. But Appasus japonicus, which has wings and carries eggs on its back, is an adult. Then you can be distinguished from the subfamily Lethocerinae by its size.

Even among larvae, there are many points of identification, such as body pattern, body size, and the size of the forelegs relative to the body size. The following photos are both first instar larvae, but there is a body size difference as early as this.

In addition, there are many identification points such as the pattern and physique of the body and the size of the front legs of the physique ratio among the larvae. The following photo is both 1-larva, but there is a body gap as early as this.

2020/11/29石川県ふれあい昆虫館でオウサマゲンゴロウモドキのことを考えた

Water stick insect is long and thin like a straw.

The water stick bug is an aquatic insect belonging to the family Nepidae with a protruding sickle on its foreleg and a long breathing tube on its elongated, stick-like body.

Water stick bug is found in relatively deep water, often in flight, and can be found in school pools.

The water scorpion has a flat, plate-like body and a long breathing tube.

The water scorpion has sickles on its front legs, a flat brown body, and a long breathing tube. In Japan, there is also Nepa hoffmanni, which is terrestrial and has degenerated wings and cannot fly.

Nepa hoffmanni, which has degenerated wings and cannot fly, has a localized habitat, while the other species inhabit the southwestern islands.

Laccotrephes japonensis inhabits shallow water bodies, but its numbers are decreasing due to the conversion to dry fields.

Laccotrephes japonensis is known for its ecology (pseudo-death) in which it stretches out its legs and pretends to be dead when held in the hand.

Types of Big Water Bug found in Japan

Basically, there is only one species of the subfamily Lethocerinae found in the wild in Japan. The larval stage is confusing in some places, such as the subfamily Belostomatinae, but it is easy to identify because the size is quite large.

Even if it is not Kirkaldyia deyrolli, many aquatic insects are decreasing in number, indicating that there is a rich wetland environment around it. Please take good care of it.

The world is wide! African Hydrocyrinus is a large Giant Water Bug. While holding the size of 5-7 cm of the same size as a Lethocerus, carry the egg on the back like Belostomatinae. Specimens are distributed relatively abundantly, and they are also exhibited in the Ishikawa Fureai Insect Museum.

Africa has Belostomatinae that grow to 5-7 cm

Looking around the world, you can see Lethocerinae has many species in Southeast Asia, America, Africa, etc. Japanese Giant Water Bug have unique features such as having a large foreleg in physique ratio,It is classified as the genus Kirkaldyia, independent of the genus Lethocerus.

On the other hand, Africa is interesting Giant Water Bug scold that becomes the size of a Belostomatinae while there is a Giant Water Bug of the genus Lethocerus. Hydrocyrinus have multiple species, but there is no detailed material.

The photo below shows Hydrocyrinus from Mali, Africa, on the left and Japanese Giant Water Bug (Kirkaldyia deyrolli) on the right.

Hydrocyrinus is as large as Lethocerinae, but its appearance and ecological characteristics are that of Belostomatinae itself.

• Unlike Lethocerinae, adult forelegs also have two claws
• Males carry eggs to protect them
• Forelegs do not spread sideways and hold up and down like mantises
• The head extends wider sideways than Lethocerinae

Hydrocyrinus has two foreleg claws, the head isNote that it is nearly twice as large as a Lethocerinae.

Japanese Belostomatinae “Appasus japonicus”

Belostomatinae is a member of the aquatic insects and lives all over the world. Appasus japonicus is about 2 cm in size.Appasus japonicus has a sickle-like foreleg, catches and eats small worms. By the 1980s, japanese aquatic insects had greatly reduced their population due to pesticides, the modernization of agriculture, and the invasion of alien species such as American crags.

Japanese Appasus japonicus is an introductory species of aquatic insects, and they are more numerous than Giant Water Bug and Diving Beetle, and can be said to be ordinary species in Japan. It is important to note that adults can be reared in groups, but the number of eggs is repeated and the number increases, and that children cannibalize.

Water supply equipment is essential for crickets that are vulnerable to drain. I made a durable water supply machine with one dollar store tappers and shoelaces, so I will share how to make it. While it was easy to use tissues and kitchen paper, there were problems with strength and durability. Both a small tapper and a shoelace are available at one dollar store, so you can mass-produce water heaters.

Self-made water supply for crickets

To give water to crickets and small insects, use insect jelly and water heaters. Crickets are vulnerable to draining water, while they have troublesome properties that kill in large quantities from ammonia poisoning derived from manure when their feet are moist. In other words, water supply equipment needs a mechanism that does not overflow with water.

To prevent water leakage, it is sucked out by capillary phenomena such as kitchen paper. The problem that this is troublesome is that the kitchen paper is bitten and it stops functioning before one is knew. In this self-made, I improved this by using shoelaces.

With one dollar store, How to make your own water supply

First of all, I will buy the smallest tapper of 3 pieces at one dollar store. Because it is small, it is easy to handle even in breeding containers. Next, make a cut with a cutter and pass the shoelace. Water supply machine completed! In addition, the material of the shoelace is not with rubber but the one of the string main is good.

Water supply equipment using shoelaces also has the advantage of being easy to understand whether it is wet or far away. Do you have any questions about kitchen paper or whether it is wet properly?

In addition, because the height is several cm, the cricket of the newborn cannot climb. Even if it is a large cricket, it is a good idea to make a ladder with a pot bottom net or the like. I also hear that you can climb with a spear, but personally it is not troublesome.

スケーター 離乳食 保存容器 ミニミニ シール容器 8個セット (4個×2) 小分け容器 保存容器 レンジOK 100ml MMS3

created by Rinker

スケーター(Skater)

• Amazon
• 楽天市場

Clover ナチュラルカラー コード 3m巻 ピンククローバー 26-190

created by Rinker

クロバー(Clover)

¥220(2025/08/07 13:34:19時点 Amazon調べ-詳細)

• Amazon
• 楽天市場

Example of water supply for crickets

The easiest way to water is to fill a tissue on the lid of a plastic bottle. The reason why the tissue is stuffed is that the cricket larva when it is small may drown and die. The problem of the tissue is that it is easy to get dirty, so it is completely replaced after water change.

2021/01/06幼虫から成虫まで！コオロギはゲンゴロウ餌の万能選手

For crickets, there are also modified water supply devices for birds.The water supply for small birds is not recommended because it is a good price from the price before remodeling.

Water scorpion is an aquatic insect.They are decreasing in number nationwide. Characteristics of water scorpion, breeding method, habitat, differences from Nepa hoffmanni and Nepa rubra etc. Water scorpion is a big species with a body length of more than 3 cm except for breathing tubes, and breeds small insects and small fish as bait. water scorpion has a rare impression than subfamily Belostomatinae and big species of the family Hydrophilidae, indicating that there is a good natural environment around it if found.

Water scorpion characterized by a flat, plate-like body with a long tail.

Water scorpion is an aquatic insect classified as the genus water scorpion of the family Nepidae. The academic name is Laccotrephes japonensis. It has a flat body and sickle similar to a scorpion, as it is called water scorpion in English. Like the Ranatra chinensis, it has a long breathing tube and a body length of 30-35 mm excluding the breathing tube. The color is brownish-brown to black-brown, and it has a habit of pseudo-dying when held in the hand.

Water scorpion’s front leg. There is a protrusion in the power hump part and it is cool. Like subfamily Lethocerinae, it digests prey by piercing a sharp proboscis.

Water scorpion’s lower body. Like Ranatra chinensis, it has a long breathing tube, but it has the impression that it lurks more on the bottom.

Males and females can be distinguished by genitals, but they can be distinguished by females with a wide and large width from males on a slightly slender body.

Water scorpion have dead pretend. There is a habit of shortening the leg and dying pseudo.

Habitat of water scorpion

Water scorpion lives in shallow wetlands, such as waterways around rice fields and reservoirs with aquatic plants. Like subfamily Lethocerinae, water scorpion had dropped sharply by around 1980 due to pesticides and development, and has since survived in hilly and mountainous areas. It is not often in the deep place that the flow is fast.

Even today, there are many factors that decrease, such as the development of concrete waterways, the invasion of crayfish, and the disappearance of shallow wetlands due to vegetation transitions and cultivation abandonment. Compared to the often-flying Ranatra chinensis, the disappearance of habitats seems to lead to the disappearance of populations. If there is water scorpion, it can be said that the environment suitable for the habitat of other aquatic insects remains.

The difference between a well-mistaken Giant Water Bug and Water scorpion

Kirkaldyia deyrolli is the biggest aquatic insect in Japan and everyone knows its name.Since the number of people who have seen Kirkaldyia deyrolli is decreasing, subfamily Belostomatinae and water scorpion are often mistaken for Kirkaldyia deyrolli. This is a specimen of the National Museum in Tokyo, but 005 is Lethocerus indicus, 006 is subfamily Lethocerinae, and 007 is water scorpion. It can be found that the size and shape are completely different, although the eating method that is digested by piercing and puncking with the sickle of the foreleg is common in the companion of the family Belostomatidae.

In addition, Southeast Giant Water Bug is famous for being imported as an insect food.

2021/12/13Differences between Giant Water Bug and similar species

Status of Endangered Species In water scorpion

Water scorpion is not an endangered species in Japan, as it is not listed on the country’s Red List(RL).

On the other hand, water scorpion has been judged extinct in Tokyo and has been designated as an endangered species in several prefectures. Specifically, in addition to CR+EN in Niigata and Okinawa Prefectures, VU in Aomori and Yamagata Prefectures,Prefecture and KochiIt is designated as NT in prefectures, Nagasaki prefectures, and Kagoshima prefectures.

However, I personally doubt whether it is better than big species of the family Hydrophilidae, which is being treated as endangered in 27 prefectures. At least the rarity in the Northern Kanto region is Appasus japonicus >>> Ranatra chinensis and Hydrophilus acuminatus Montschulsky > Water scorpion > appear to be a Kirkaldyia deyrolli. Both the points and individuals found have a smaller impression than the Hydrophilus acuminatus Montschulsky.

It may be a pattern that water scorpion is not listed in the RL of each prefecture, although it is actually decreasing, but nothing is specified due to lack of information.

2021/08/09ガムシは国の“準絶滅危惧種”で絶滅危惧種になっている県もある

Water scorpions are actually decreasing in many areas, but RL may not reflect this.

When I asked about the habitat status of water scorpion on Twitter, they told me that it is decreasing in various places. Some prefectures are rarer than other endangered species, but they are not on the Red List. It may be a pattern that will disappear while thinking that it is a normal species. I would like to be concerned about the decrease in habitat spots.

For example, according to a person related to the revision of the Red List in Ehime Prefecture, he plans to include water scorpion in the next revision. Shallow such as water scorpion depends is easy to be land by vegetation transition, and if you do not manage a pond for agriculture, fallen leaves accumulate and become unsuitable for habitat.

Water srorpion was seen in Hyogo-prefecture from the 1990s to the 2000s, but after that,it was not seen.

In Azumino City, the number of water scorpion is smaller than that of Appasus japonicus and Hydrophilus acuminatus Montschulsky.

In Ishikawa Prefecture, water scorpion is rarer than the endangered Cybister japonicus.

How to feed and breed water scorpion

Breeding water scorpion is not so difficult. Prepare a container with scaffolding at a depth of about 5 cm to 10 cm, and feed on aquatic insects or small fish. The leftovers will stain the water, so replace it as appropriate. There is a hassle of living food, but small fish can be bought anywhere, so it is easy.

In the wild, you’ll hunt ambush-shaped to hide in the mud and capture passing bait. The amount of exercise is small, and food is not required every day. You only have to put the small fish of about the same number as the number of individuals. When the water depth is shallow, such as several cm, crickets floating on the surface of the water can also be used as bait. I have never given it, but it seems to be able to go around small shrimp. However, it hurts water, so let’s remove the leftovers immediately.

The life span is several years, and winter on land. Around November, they hide in moist fallen leaves, etc. and put it in a cool dark place, it will hibernate without permission. When it gets warm in the spring, let’s wake it up them. I think that it can be the same feeling as the hibernation method of the Kirkaldyia deyrolli. In captivity, it is okay even in water wintering, and the container is placed in a place where the water temperature is stable, such as in the shade.

2020/12/15タガメの冬眠時期や方法について

Water scorpion lays about 10 eggs on the ground, such as moss moistened in early summer and an oasis for fresh flowers. The photo shows a similar type of Nepa hoffmanni egg, and water scorpion’s egg has a beard as well.

Differences from Nepa hoffmanni and Nepa rubra

Among water scorpion’s companions are the smaller Nepa hoffmanni and overseas there is a Nepa rubra, nearly 1.5 times larger.

Nepa hoffmanni is a small water scorpion with a body length of about 20 mm. In Japan, it lives in a limited area.Laccotrephes japonensis is rarer in the vicinity of Nagoya.

The wings of Nepa hoffmanni degenerate and cannot fly. It lives in the water’s water’s perident and wet track and field areas, which have been kept by spring water. The breathing tube is also short, and if you throw it into a container only of water, you may drown and die. Because of its low mobility capacity, it can be said that it is extremely weak in development.

As the name 2010 is,Nepa rubra is a big water scorpion inhabiting Southeast Asia. I’ve never even seen a living body. The body length excluding the breathing tube reaches 40-45 mm, and it is nearly 1.5 times that of water scorpion in Japan. Living organisms are sometimes distributed in Japan, but it is expensive.