Giant Water Bug Life Cycle: Exploring Nature’s Fascinating Predators

Giant water bugs are fascinating creatures known for their predatory nature and impressive size. Reaching up to 2-3 inches in length, these insects are among the largest found in North America and Minnesota. With their dark brown coloring and banded raptorial legs, they are highly skilled at capturing prey in aquatic environments.

The life cycle of these intriguing insects consists of three main stages: egg, nymph, and adult. Female giant water bugs are known to lay over 100 eggs on the backs of their male counterparts. Males play an active role in ensuring the successful hatching of their offspring by stroking water over the eggs with their legs.

As nymphs, the immature giant water bugs remain concealed in the water, often hiding among plants. Throughout their life cycle, these insects demonstrate remarkable adaptability and serve as important predators in various aquatic ecosystems.

Giant Water Bug Identification

Physical Features

Giant water bugs, belonging to the family Belostomatidae, are large aquatic insects found in various habitats across North America. A common species of giant water bug is the Lethocerus americanus, which can grow up to 2-3 inches in length. They have a dark brown color and several noticeable features:

• Oval-shaped body
• Pincer-like front appendages
• Banded raptorial legs (for capturing prey)
• Snorkel-like breathing tube

An additional characteristic of these bugs is their wings. Adult giant water bugs have a leathery base on their front wings, with the outer wing areas being more membranous.

True Bugs Versus Insects

Giant water bugs are classified as true bugs, belonging to the order Hemiptera. While all true bugs are insects, not all insects are true bugs. Here’s a comparison table for true bugs and other insects:

Giant water bugs are one of the many diverse species within the true bugs category. Their distinctive physical features, such as the pincer-like appendages and snorkel-like breathing tube, make them unique among the various aquatic insects found in North America.

Giant Water Bug Habitat

Freshwater Environments

Giant water bugs prefer freshwater environments to live and thrive. They are commonly found in:

• Ponds
• Streams
• Lakes
• Marshes
• Ditches

These bugs are highly adaptable, being able to survive in slow-moving or stagnant waters.

Geographical Distribution

Giant water bugs have a wide geographic distribution, spanning several continents:

• North America
• Asia
• Africa

Some species can also be found in South America.

Here is a comparison table of giant water bug habitats:

The state of Texas in the United States has a significant population of these bugs. Overall, giant water bugs are an integral part of various freshwater ecosystems, contributing to the balance of these habitats.

Life Cycle and Development

Eggs and Nymphs

• The life cycle of giant water bugs begins with the female depositing eggs on the back of the male. This can count up to 100 eggs or more¹.
• Males assist hatching success by stroking water over the eggs with their legs¹.
• Nymphs go through different stages, known as instars, as they grow².

Giant water bugs (Lethocerus sp) prefer to lay their eggs on vegetation in slow-moving or stagnant water³. Aquatic immature stages, or nymphs, often conceal themselves among plants during development¹.

Adults and Mating

The nymphs transform into adults after undergoing multiple instars². Adult giant water bugs can reach up to 2-3 inches in length, making them one of the largest insects in North America³.

Mating season occurs during the warmer months of spring and summer³. After mating, some giant water bug species are known to overwinter in plant roots and debris⁴.

Comparison Table: Giant Water Bugs Life Cycle

Feeding and Prey

Prey Selection

The Giant Water Bug may target several types of animals for food. Examples of prey they often prefer include:

• Tadpoles
• Small fish
• Insects
• Snails
• Crustaceans

These predators inhabit freshwater habitats such as ponds, marshes, and slow-moving pools worldwide.

Feeding Mechanisms

A remarkable aspect of the Giant Water Bug’s feeding mechanism is its digestive saliva, which it injects into its prey. This saliva liquefies the insides of the prey, allowing the bug to consume its food by sucking it out.

Pros of their feeding method:

• Helps control population of other insects and organisms
• Strengthens ecosystem dynamic

Cons of their feeding method:

• Might impact sensitive aquatic life species
• Not a significant source of food for other predators

In summary, the Giant Water Bug plays a role in its freshwater habitat by preying on various organisms. Its unique feeding mechanism, using digestive saliva to break down prey, allows it to capture and consume a variety of prey effectively.

Behavior and Adaptations

Defensive Mechanisms

Giant water bugs are known for their venomous and painful bites. They use these bites both for feeding and as a defensive mechanism. When disturbed, they may deliver a painful bite, earning the nickname “toe-biters.”

Breathing

Breathing is vital to these aquatic predators, with their unique adaptation of a breathing tube. This tube, called siphons, allows them to breathe while submerged underwater. The siphon extends to the water surface, enabling oxygen intake.

Locomotion

The locomotion of giant water bugs includes their flattened rear legs. These legs have tiny hairs (cilia) that help propel them through the water¹. Even though they are relatively large insects, most giant water bug species are not flightless².

Distribution and Feeding:³

• Largest species: Lethocerus americanus
  • Up to 2-3 inches in length
  • Distribution: North America and Minnesota
• Feeding habits: Predatory insects, attacking prey up to 20 times larger in size
• Male giant water bug: Known for carrying eggs on its back

Characteristics:

• Dark brown color
• Banded raptorial legs: Adapted to catch and hold prey
• Proboscis: Sucking mouthparts used for feeding
• Not all species are flightless

Subfamilies:

• Belostomatinae
• Lethocerinae
• Horvathiniinae

Human Interaction and Other Names

Common Nicknames

Giant water bugs, belonging to the order Hemiptera and the family Belostomatidae, are known by various names. Some common nicknames for these predatory insects include:

• Toe-biter
• Electric light bug
• Alligator tick

Bites and Potential Hazards

Although giant water bugs, such as Lethocerus americanus, Lethocerus indicus, and Lethocerus uhleri, are not generally aggressive towards humans, they can deliver a painful bite when provoked or mishandled. They possess a sharp beak (rostrum) to inject digestive enzymes into their prey, which include frogs, cockroaches, and spiders.

Giant water bugs can be found in freshwater ponds and other aquatic environments where they prey on small organisms and feed on aquatic vegetation. Their presence impacts the ecosystem by keeping populations of smaller organisms in check, ensuring a healthy balance. However, they may also pose a threat to native wildlife if introduced to new habitats. Some potential hazards of giant water bugs are:

• Painful bites to humans
• Alteration of ecosystem balance if introduced to new areas

Giant water bugs are valuable as a food source in some regions, particularly in Southeast Asia, where they contribute to the local cuisine. Additionally, their unique features and behavior have made them a subject of interest for researchers and bug enthusiasts.

To better understand the differences among common giant water bug species, the table below presents a comparison of key features:

(always remember to handle these bugs carefully in case of encounters, and appreciate their role in their natural habitat)

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Giant Water Bug, AKA Toe-Biter

Giant Bugs in Indiana?
Location: Found dead in NW Indiana
March 20, 2011 9:53 pm
Greetings!
I work at a hotel in NW Indiana and happened across this guy in the parking lot. I’m thinking that maybe it hitchhiked on someones car (at least thats what I’m hoping) because I’ve NEVER seen a bug this big in Indiana before… Please help me identify this bug!!! My thinking is that it’s a beetle of some sort.. a few people suggested a cicada but its MUCH bigger then those guys :p
Signature: A little freaked out — Molly

Hi Molly,
The Giant Water Bug or Toe-Biter is a local insect for you.  You have probably not seen them before as they are an aquatic species that inhabits still bodies of water like ponds, lakes and swamps.  As adults, Giant Water Bugs fly quite well, and they are often attracted to brightly lit locations like parking lots, hence another common name, Electric Light Bug.  The Giant Water Bug is the largest True Bug in North America, though it is dwarfed by closely related species in Southeast Asia which grows to about five inches in length.

Letter 2 – Thai Treats: Roasted Giant Water Bugs

Giant Water Bugs
I have enjoyed reading your informational site. I borrowed one of your photos to illustrate the portion of meat I ate when stationed in Thailand in 1969. The Giant Water Bugs were collected under the street lights at the Korat Air Base, in central Thailand. The native guards would roast them over a little campfire. They taught me to stick a bamboo skewer into the abdomen and slowly roast them. They peeled the exoskeleton behind the head to reveal a tasty morsel of white meat. The taste reminded me of a small sweet scallop. The guard did not have me eat the whole bug, but I understand they can be fried or roasted and eaten whole. At the time the locals called them Baht Bugs because the people could sell them for 1 Baht each at the market. The value was 5 cents at the time. That was fairly valuable since a man working hard labor in the hot sun would only make 15 cents per hour. Our guard supplemented his income by collecting dozens of the Water Bugs, putting them in burlap bags.
I forgot to add my name Thanks for maintaining such a great website.
Lucky Ketcham
San Diego, CA

Hi Lucky,
Thanks for the great anecdote. We will post your letter to our Edible Insects page.

Letter 3 – Male Giant Water Bug with eggs

WEIRD F%(#!N BUG THING!!! HELP!!!
Wed, Nov 19, 2008 at 12:22 AM
So like dude i was in the kitchen and all of a sudden this thing just comes crawling out from under the stove, i was scared man. It’s not exactly the kindest looking bugs. I don’t know anything more than that really, i swooped it up with a dustpan and let it wander outside.
tittysprinkles
My house in Tacoma Washington

Dear tittysprinkles,
Generally we refrain from editing the letters we receive, but as so many youngsters access our website, we felt compelled to “bleep out” your subject title.  This is a male Giant Water Bug in either the genus Abedus or the genus Belostoma.  When they mate, the female cements the eggs to the back of the male and he is the primary care giver for the unhatched brood.  We are amazed that he was able to fly to your kitchen with that payload on board.  Giant Water Bugs are aquatic, but they can fly quite well and they are attracted to electric lights.  We suspect there is a body of water nearby that served as a mating habitat for your specimen.

Letter 4 – Haitian Toe-Biter

what is this bug i found in the mountains of Haiti
Hello,
I found this bug in our garage. I live in port-au-prince, haiti at about 3000 feet above sea level.
Thanks,
Joel Trimble

Hi Joel,
This is a Giant Water Bug, also known as a Toe-Biter. They are aquatic insects that can also fly. While flying they are attracted to electric lights, owing to another common name, Electric Light Bug. Perhaps the garage light attracted it.

Letter 5 – Male Giant Water Bug with Eggs

What is this?
Location: Palm Canyon, near Palm Springs, CA
April 1, 2011 6:17 pm
We saw this bug in the cold, cold water near Palm Springs, CA the first week of March. (Palm Canyon – Stone Pools). It stayed undewater for a while and then came up and seemed to breathe through a tube that came from its rear end. Pretty large bug…not sure what is on its back….babies?
Signature: Mary, Asheville, NC

Hi Mary,
This is a Giant Water Bug, and it is something of an anomaly in the insect world in that the male of the species cares for the eggs, which are cemented by the female onto the back of the male.  The most commonly encountered Giant Water Bugs are the Toe-Biters in the genus Lethocerus, but that genus does not exhibit this paternal care.  Two other genera, Abedus and Belostoma, are both found in California, and they both exhibit paternal care of the eggs.  Alas, we haven’t the necessary skills to determine which genus your individual belongs to.

What a great website!!!!   Thanks!  I wonder how many people stumble upon a Giant Water Bug with babies cemented on its back breathing through a tube!  So cool!
Mary

Letter 6 – Giant Water Scavenger Beetle

Any help identifying this bug?
St. Louis, MO.
Just found it out on the front lawn and never seen one like it. About 2 inches long and 1/2 inch wide. Thanks.
sent in by Taylor and Morgan Ratliff

Dear Ratliff Family,
This is a Giant Water Scavenger Beetle, Hydrophilus triangularis. These beetles are found in ponds and slow streams throughout North America. They leave the water and fly on summer nights and are often attracted to lights. They eat the decaying remains of aquatic animals and occasionally feed on small living animals. This is a new species for our site.

Letter 7 – Immature Giant Water Bug

Green Water Beetle?
August 9, 2009
Every year at my cottage me and my friends put together a small aquarium of insects and other animals that we find in our lake. This year we were surprised to catch something none of us had ever seen before. We thought at first that it was a baby Giant Water Beetle, but later on in the trip we caught another one identical to the first in an entirely different part of the lake. This lead us to believe that it was probably something different. I took some pretty good pictures of them before they were released and I was hoping you might be able to help us figure out what they were.
Max
Southern Ontario

Dear Max,
This is a Giant Water Bug in the genus Belostoma, and it is an immature specimen.  Mature specimens have wings and can fly.  Most Giant Water Bug images we receive are the much larger members of the genus Lethocerus.  Your one image shows an orange speck on the right hind leg that appears to be a mite.

Letter 8 – Immature Giant Water Bug

WTB
I have posted pictures of this bug. Found in shallow water (and released) chasing another smaller bug. It bit me.

This is the first time we have gotten a photo of an immature Giant Water Bug, or Toe-Biter. Adults have wings and are strong fliers. There are human encounters when they are attracted to lights, hence their other common name, Electric Light Bug.

Letter 9 – South American Toe-Biter

Toe-Biter
AMIGOS : desde sud America les escribo para felicitarlos por su pagina y la tarea de divulgacion y formacion que realizan, aprovecho para enviar foto adjunta con nombre de hemiptero que les mando Toe Biter con el genero y especie es acuatica y aqui se las llama chinche gigante de agua saludos
Dr Carlos Marzano

Hola Dr Carlos Marzano,
Muchas gracias para su photo excellente de Belostoma cummingsi, un Hemiptero aquatico de Sudamerica.

Letter 10 – Iraqi Toe-Biter

Giant IRAQI Water Bug?
I looked at your site and noticed a lot of photos of "toe-biters", or "giant water bugs." I noticed a lot were Canadian. I’m in Balad, Iraq, and noticed the photographed/attached bug here during our rainy season, and it looks identical. Is it possible that this bug lives over here as well? It was VERY aggressive, and waddled when it walked.
Hans in Iraq

Hi Hans,
Thanks for sending in your image of an Iraqi Toe-Biter. There are species in most parts of the temperate and tropical world. In Southeast Asia where they grow to five inches long, they are a deep fried delicacy. Don’t get your finger too close as they do not distinguish between fingers and toes.

Letter 11 – Madagascar Toe Biter

Whats That Bug?
Hello Whats That Bug?
I had another encounter with a nightactive "i will kill myself in the lamp" oversized bug. I found it in a hotel on the beach of Nosy Be as well as in the central highlands of Madagascar.
Thank you,
Kati

Hi Kati,
This is a Giant Water Bug, known stateside as Toe Biters for a really good reason.

Letter 12 – Smelly Corpse of a Toe-Biter

Toe Biter
HI. I found one of these Water Scorpions dead in my living room and did not know what it was until I found your site. After I found it, I put it in a box with a lid, and the next day when we opened it, it smelled like a dead corpse. Can you tell me why?
Gina

Hi Gina,
Your dead Toe-Biter began to smell like a corpse because it is a corpse. Insect collectors preserve most specimens by letting them dry out. If you placed the still fresh specimen in an enclosed space, it could not dry and began to decay, hence the smell. Your specimen appears to be a Giant Water Bug, Lethocerus americanus, and not one of the Nepa Water Scorpions which rarely fly. We are getting a second opinion on the very long breathing tube your photo illustrates, and are unsure if this is an individual anomoly. Your image is beautiful.

Letter 13 – The other Toe-Biter

Strange water bug near Tucson
Hello Bugman!
Thanks a lot for informing me on the Dolomedes spider! First described 1973 – really rare arachnid, as it seems! In a pool nearby some of these poor creatures were swimming – in a pond one inch deep! The sun was shining directly onto them; and they could only hide under some small rocks. I don’t know if they made it to the next monsoon season. I took this guy and threw him into a larger pool with lots of amphibia larvae. Hope he didn’t eat ’em all up! Do you have any idea what kind of water bug that might me? About 3 cm long; and with a fang of at least 4 mm, as I observed on a dead speciman. Thanks a lot!
Greetings from Daniel Jestrzemski

Hi Daniel,
This is a Giant Water Bug in the family Belostomatidae. They are frequently called Toe-Biters. This is not one of the species in the genus Lethocerus, the most frequent submissions to our site. We believe this is Abedus indentatus, but sadly, there is only one image on BugGuide of a male encrusted with eggs and that image does not show the outline of the insect. Charles Hogue describes the species in Insects of the Los Angeles Basin, but once again, the image is of a male encrusted with eggs. If this is not Abedus indentatus, then it is in the genus Belostoma, also pictured on BugGuide. Our reasons for believing this to be Adedus as opposed to Belostoma are based on the shape of your specimen. The abdomen is rounded as opposed to pointed and the thorax of your specimen is shaped differently than Belostoma as well. Perhaps when Eric Eaton contacts us, the mystery will be solved.

Daniel:
I believe the toe-biter in question is in the genus Abedus. Not sure how many species there are in California.
Eric

Letter 14 – Potfull of Toe-Biters

Unknown Bug
Hello
We have these bugs that just show up this time of year. We live just out of Dawson Creek B.C. Canada. They don’t live long as it gets cold at night. We have checked the web and can’t seem to find what they are. I think they come with the warm winds we get this time of year. One got on my husband finger when he was taking the pictures and he said it felt like it had little barbs like a blade of grass. It sure would be nice to find out what they are. Thanks
Debbie

Hi Debbie,
We find your potfull of Toe-Biters, or Giant Water Bugs, quite amusing. Larger relatives of the American species are eaten as a delicacy in Thailand.

Letter 15 – Male Giant Water Bug with Eggs

Water bug with eggs (and others)
Thanks for posting my Polyphemus picture! Here are some others you might like. One is a picture of a large water beetle of some kind. I believe it is the male bug, and the female has laid her eggs on his back. Do you know what it is? Also, I have included a shot of what I believe to be a Woolly Bear caterpillar, though I have never seen a "blonde" one before! Is my identification correct? The dragonfly picture I have attached is of a male Spangled Skimmer eating some other bug for breakfast. Lastly, I have included a picture of a Praying Mantis egg case, with the baby insects emerging. All of these pictures were taken at Goose Pond Mountain State Park in Chester, NY (southern NY). Thanks again!
Kat

Hi Kat,
Thanks for submitting your other images. We do not have the time nor the wherewithall to deal with multispecies letters. Should you decide to submit anything in the future, please only submit photos of one species per letter. Forced to choose, we decided to post your male Giant Water Bug, Belostoma lutarium. The female cements the eggs onto the back of the male. This species shares the names Giant Water Bug, Toe-Biter and Electric Light Bug with the more frequently seen Lethocerus americanus.

Letter 16 – Taunting a Toe-Biter in Iraq

Toe Biter
My friend and I found this while walking late at night. We’re in Iraq, based in Balad Air Base. He was basking in the light of a standalone, stadium light, generator. He was pretty unresponsive for the first few touches, then he started to run away. I have a short video of him crawling across the ground if you would like.
Nicholas

Hi Nicholas,
We bet you wouldn’t be taunting that Toe-Biter that way in your bare feet. Though ungainly on land, Giant Water Bugs are extremely efficient swimmers and quite aerodynamic in flight as well. They have earned their common name due to the painful bite experienced by chance encounters with swimmers. We have been wanting a compelling new photo of a Toe-Biter for our homepage because this is one of the insects that are constantly featured there, along with Pseudoscorpions and House Centipedes.

Letter 17 – Giant Water Scavenger Beetle

black beetle
Found this beetle in our grass. We tried to identify it on the internet, but no luck. We live in Boise, Idaho. Our son loved watching it roam. We hope our trees aren’t in danger. Any guesses? Thanks-
Brandon

Hi Brandon,
Your trees are safe. This is a Giant Water Scavenger Beetle, Hydrophilus ovatus. Though aquatic, they can fly.

Letter 18 – Giant Water Scavenger Beetle

Water bug?
I believe this bug that we saw swimming along the margin of a submerged boulder in Millard Canyon Creek (Angeles National Forest at ~1600 foot elevation, in the Altadena foothills, CA) is some form of giant water bug (toe biter), but it looked slightly smaller with a shinier carapace than most giant water bugs I’ve seen. It was about 1.5 inches long. Can you identify it for me? We left it puttering around in a fairly still, algae-filled pool in the shallow creek. Buggy Best Wishes!
Lori

Hi Lori,
Not a Giant Water Bug, but a Beetle. Eric Eaton corrected us on this by writing in:”Hi, Daniel: The Predaceous Diving Beetle” is actually a Giant Water Scavenger Beetle, probably Hydrophilus triangularis. Dytiscids that large are usually outlined in yellow, which is one way I tell them apart. Hope all else is going well! Take care. Eric ”

Letter 19 – Male Toe Biter carrying Eggs

baby mantids, toe biter, and painted lady butterfly
Hello! First, I’d like to let you know that my kids and I are huge fans of your site! My four year old son, in particular, is quite the insect enthusiast and loves to look at the photos on your site. We don’t need help identifying the insects in the attached photos, but thought you might like them. We had a praying mantis egg case that hatched just this morning. It was so exciting to wake up and find hundreds of adorable baby mantids waiting for us! I took a couple of photos before we released them into our garden. I’d also ordered some painted lady caterpillars, which the kids and I raised and had a lot of fun observing. I took a photo of one before we released it, also this morning. Finally, yesterday I took the kids to a local park where we caught this incredible toe biter. We’d only ever seen them in books, so we were thrilled to observe a live specimen. Thanks to your site, we know it’s a male with the eggs cemented to his back. We gave him a couple of tadpoles in case he gets hungry, but so far he’s left them alone. The toe biter got to spend the day at preschool with my son, and after dinner we’re going to take him back to the park. Our question is, can a toe biter fly when he has eggs stuck to his back? Thanks so much for the amazing site! We’ve all got our fingers crossed that at least one of our photos makes it onto the site. You don’t want to disappoint a four year old, do you? We know you’re really busy this time of year–keep up the great work!
The Ganino Family
Ps We live in Connecticut, near the shoreline!

Dear Ganino Family,
The problem with using strictly common names for identification purposes is that they tend to overlap. Your Toe Biter is in the genus Belostoma, smaller individuals than the more commonly submitted larger Lethocerus species. The Lethocerus do not cement the eggs to the back of the male like the Belostoma do. Males cannot fly while the eggs are being carried about.

Letter 20 – Male Giant Water Bug Tends to eggs as female eats

February 24, 2010
Giant Water Bugs
Hi, WTB,
I’ve been going through photos from last summer and I thought that you might be interested in some Giant Water Bug images that have a little more detail (including particulate gunk in the water — sorry for that) than is sometimes seen in field photographs.
The first image gives an idea of the male behavior of, what seems to be, aerating/hydrating (and, perhaps, cleansing?) the eggs by rapidly moving his back in and out of the water.

The second shot shows a submerged male with all of the eggs, and only the eggs, above the surface.

The third photo is of a completely submerged male and eggs.  You just can see the very tip of his backside breaking the surface.

The final shot is of a, presumably, female — totally submerged — who is feeding “up” on the food chain.
Early July, foothills of the Santa Rita Mountains, southern Arizona, about 4,400 ft.
Denny Schreffler

Dear Denny,
You are continuing a pattern of excellence with both your photos and your verbal descriptions.  These documentations of a Male Giant Water Bug in the genus Abedus, probably Abedus herberti which BugGuide reports is found in Arizona, are positively spectacular.  The focus and detail are superb, and the observational information on the aeration/hydrating/cleaning behavior of the male with the eggs is a wonderful addition.  The Giant Water Bugs in the genera Abedus and Belestoma are interesting in that the female cements the eggs to the back of the male after mating, and the male has the responsibility of protecting the eggs, though once the eggs hatch, he is freed of his duties.  Thanks so much for including the information that the photos were taken in July, because so often our readers submit images that are many years old and they fail to include such relevant information.  Though your photos are quite detailed, you neglected to indicate what prey was captured in the Food Chain image, other than that it is up the food chain.  Is it possible to provide that information?

I don’t know what fleshy little vertebrate morsel she is eating — I came upon her after she already had been through the carry out line — but it probably tastes like chicken.
Thanks for the nice comments.
Denny Schreffler

Eric Eaton Agrees with identification
Hi, Daniel:
The giant water bugs from Denny here in Arizona are the species Abedus herberti.
Eric

Letter 21 – Immature Giant Water Bugs exhibit cannibalistic behavior

yellow bettle? aquatic?
Location: Raymond, California
August 7, 2011 3:45 pm
I saw these two insects this morning in one of our creeks. They were both approximately the same length, but obviously different colors. The yellow one was firmly grasping the dark one – mating? Predation?
I am clueless on ids for both of them. Any ideas?
Signature: Megan Ralph

Hi Megan,
We are confident that we have identified your insects as two immature individuals of a species of Giant Water Bug in the genus Abedus, based on this image of Abedus herberti posted to BugGuide.  The yellow individual in your photos and the BugGuide image are newly molted nymphs in the teneral stage, meaning that their exoskeleton has not yet hardened and darkened.  Insects are especially vulnerable immediately after metamorphosis.  We believe the dark individual in your photos, also a nymph, is taking advantage of its weaker coeval by preying upon it.  Of course, your photos do not reveal the final outcome, and the teneral individual may have actually been the victor in this food chain drama.  BugGuide has a wealth of information on Abedus herberti, including this listed range:  “Arizona, Utah, New Mexico, USA; northern Mexico” and this listed habitat:  “Freshwater streams, especially in montane areas. They often inhabit intermittent streams, so they are isolated to individual rock pools (tinajas) during dry periods when streams do not exhibit overland flow.”  This interesting note of food may explain the cannibalistic behavior that your photo illustrates:  “All water bugs are predators. Abedus herberti eats other insects, small fish, small tadpoles, and will become cannibalistic when other food is scarce.”  One final bit of information from BugGuide indicates that this might actually be a closely related species from California, Abedus indentatus:  “Abedus is a difficult genus in which to identify species without a microscope for close examination. A. heberti is similar in appearance to most other Abedus species, but it is most similar to Abedus indentatus. A. indentatus is typically only found in California.”  BugGuide has a dearth of information on the California species.

Thank you so much for your detailed and extremely informative reply.  That is the perfect description for the habitat where I saw them – a small stream that is beginning to dry up (rather late in the year actually – it was a wet spring).
Megan

Letter 22 – Not Satan’s Pet: Giant Water Bug

Subject: I am certain this is Satan’s pet.
Location: San Juan, Puerto Rico
May 30, 2013 11:30 am
My friend found this bug in her house in Puerto Rico yesterday. Right now it is in between pluvial and dry season (the only seasons we have in PR). She had her husband pick it up and throw it out the window (she lives in a 3rd floor) and this demonic-looking guy FLEW. It was quite large, about a dollar bill large (or a little bit bigger).
While she doesn’t live in a rural area, it is not uncommon to see rainforest creatures in the urban areas of Puerto Rico.
Signature: Melissa Dailey

Dear Melissa,
This is not Satan’s Pet.  It is a Toe-Biter or Giant Water Bug and it is reported to have quite the painful bite.  Though they are aquatic predators, Toe-Biters or Giant Water Bugs also fly quite well.  They are attracted to lights at night, earning them yet another common name:  Electric Light Bug.  Your letter will not go live to our site before early June since we are going to be away from the office, but we want activity on our site.

Letter 23 – Male Giant Water Bug with Eggs

Subject: please help me identify this bug
Location: near austin Texas
July 4, 2015 1:36 pm
I found this bug swimming in my pool before i was going to clean it. Whatever is on its back looks interesting and im not sure how to identify it. I saw it swimming for a while then it nestled on the bottom of the pool. When i nudged it with a small stick to see if it was still alive it was not. So i carefully took it out and captured a picture of it. Any help would be appreciated. Thank you.
Signature: From Troy Godwin

Dear Troy,
This is a male Giant Water Bug in the genus Belostoma.  After mating, the female cements the eggs onto the back of the male who then guards them until they hatch.  This is one of the very few examples from the insect world where the male plays any part in the care of the young.  You can verify our identification by viewing this image from BugGuide.

Letter 24 – Giant Water Scavenger Beetle

Subject: Odd beetle/roach
Location: Johnston, Iowa
July 19, 2015 8:52 pm
Hi there,
My dad and I found this bug in a window well behind our house while cleaning out a lot of leaves. The bug was pretty big- as large as any roach that I’ve ever seen in Iowa.
The window well is on the north side of the house and behind a large hosta. A couple weeks ago the downspout detached and with 5″ of rain the well flooded and water flowed into the basement through the window. So it is fairly moist down there. We also found two frogs/toads in the well.
Anyway, this bug was found on 7/19/2015 in Johnston, Iowa. Our neighborhood is relatively flat and we live within half mile to a creek that eventually feeds into the Des Moines River.
Signature: Coen Wiberg

Dear Coen,
What a nice discovery.  This is a Giant Water Scavenger Beetle in the genus Hydrophilus which you can verify by comparing your image to this image posted to BugGuide.  According to BugGuide, they can be found in:  “stagnant/slow waters; prefer deeper water (weedy ponds, deep drainage ditches)” and “Some adults overwinter on land, under leaf litter. Others may remain under ice of ponds and stay active all winter. Lifespan may exceed one year. Adults may be found at lights in summer as they disperse.”  If there was a light in the window well, it might have attracted this Giant Water Scavenger Beetle, and if there was also water present at the time, it may have found the location to its liking.