CRITTERS AT BBSP AND ELSEWHERE  Water Insects
This page was born 10/11/2024.  Rickubis designed it.  (such as it is.) Last update: 11/08/2024
Images and contents on this page copyright © 2002-2024 Richard M. Dashnau  

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This page features insects that live and hunt in (and on) water. I'm including insects that have a larval or nymph stage that lives in water, although
the adults might not (such as dragonflies). The most recent events will be at the top of the page, with older observations as you move down. I
was inspired to create this page because of research I did recently (2024) about water bugs. The picture above shows our collection table
during a pond life program on the Spillway Trail in 2019--featuring an assortment of water insects (which all happen to be true bugs!) and a few other
animals (freshwater shrimp, tadpole).

On 10/20/2024 I helped with another Pond Life Program, and we found a few water bugs. These are Lethocerus species (I can't tell which one). The last image shows an adult and a nymph-
they weren't staying together-I just happened to take the picture when they moved by each other.


The first image below was taken outside on the program table. The second image was taken inside the Nature Center, after all the captures were put into the aquarium display.
They are nymphs, also. I believe they are nymphs because they don't have wings, and Lethocerids because of their size. The third image shows one of the Lethocerid nymphs nest
to a an adult of a different species of Giant Water Bug--a Belestoma species. Both of them had their snorkels at the surface. Note the one on the left has wings, and also has a point on
the tail end. The 4th image shows the Belestoma adult swimming by the Lethocerid. Quite a size difference, there!  Note the longer "snorkel" on the Lethocerid. The other creature is a
dragonfly nymph.The fifth image shows a Belestoma out of the water, feeding on a dragonfly larva.

There's one more thing. Although we can see water bugs breathe air by putting their back ends to the surface (that's where their snorkels are)--a few  species carry air back under water
with them. One species carries a bubble under its wings and over its spiracles. Another uses a small trapped air bubble as a gill--by moving its wings, which changes compression of the
bubble, and induces diffusion of gases of the water to and from the air held inside the bubble! That is-oxygen diffuses in, and carbon dioxide can diffuse out. Holy cow! (2011 goforth)


09/29/2024  At Brazos Bend State Park, I noticed something large caught in a spider web on the North loop of 40 Acre Lake trail.It was a Giant Water Bug! 
I couldn't get too close because the web was over the water. I only got a few pictures.  The spider seems to be a Tropical Orb weaver (Eriophora ravilla). The insect was a really
 big "giant water bug". Various sources describe them as highly effective predators-feeding on many kinds of invertebrates and vertebrates!  Yet, this bug was subdued by a
smaller arthropod (the spider), aided by the technology of the spider's web. I consider the web "technology" because it was built by the spider, and is maintained by the spider
for its use. A vertical orb web contains 3 different types of thread which comes from 3 different types of silk gland. And one of those threads is made sticky by glue from a fourth
 type of silk gland. An orb web can disperse the force of a flying object by stretching in the direction of motion, and then moving back into shape, with the object immobilized and
 glued in place.(from the book, Spider Silk by Leslie Brunetta and Catherine L. Craig ©2010) Sounds pretty technological to me. But...I'm talking about the prey this time--the Water Bug.


I was inspired to learn more about Giant Water Bugs. After 19 articles, I discovered many amazing things. The information below is mostly from these 4 sources. They have
summarized much of the information in the other studies:
1) 2009_Identifying American Giant Water Bug Genera _Goforth_
2) 2011 Subsurface behaviours facilitate respiration by a physical gill in an adult giant water bug, Abedus herberti  by Goforth et al
3) 2016 Venoms of Heteropteran Insects: A Treasure Trove of Diverse Pharmacological Toolkits by Walker et. al.
4) 2018 Ecology of giant water bugs (Hemiptera: Heteroptera: Belostomatidae) by Shin-ya Ohba

When I've assisted with the Pond Life programs, I've wondered about the term "giant water bug" as it applied to the different-sized ones we caught.  "Giant water bugs" are an
 entire family of insects (Belostomatidae), including about 150 species. It contains two subfamilies:  1)Belostomatinae 2)Lethocerinae.  I believe we've encountered Giant Water
 Bugs from both of those families during our  pond life programs. The ones that have always impressed me (and they include the largest species) are in Lethocerinae.
One of those was caught in the web this morning. Bugs in Belostomatinae deposit their eggs on the males' backThose in Lethocerinae deposit their eggs on emergent plants.
 
From Ohba 2018: "Belostomatinae does not digest vertebrates well, because the saliva does not have enzymes capable of digesting protein-rich meals such as vertebrate animals."
 "Lethocerinae, the largest-bodied subfamily in Belostomatidae,  prefer to eat mainly vertebrate animals such as fish and anurans. For example, Lethocerus americanus prefers to
 eat larger fish." some  researchers observed Lethocerus attacking birds and water snakes. In recent years, it has also been reported that K. deyrolli eats snakes and turtles in their
 habitats in Japan. Therefore, giant water bugs should be regarded as higher consumers of wetlands as well  as vertebrate predators."

So t
hese insects can feed on animals all over the food chain. Water bugs are in the order Hemiptera (true bugs), distinguished from other insects mostly by their mouth parts. The
mandibles and maxillae (which we can easily see in other insects) also exist in true bugs, but  are modified to form a "beak" with a complex structure including separate tubes that
 allow for application of venom/enzymes and ingestion of liquefied food.  And--true bugs are venomous.
 

from Walker 2016:
"Venom is a secretion, produced in a specialized gland in one animal, and delivered to a target animal through the infliction of a wound.   A venom must further
 contain molecules that disrupt normal physiological or biochemical processes so as to facilitate  feeding or defense by the producing animal. Unfortunately, there is a historical
tradition among entomologists and venom researchers to confuse or discount  the venomous nature of heteropterans."

"Envenomation typically occurs in a swift strike in which  the mandibular and maxillary stylets penetrate the food source and venom is injected, sometimes accompanied by grasping
 or gripping with the forelegs or  fore- and mid-legs. Within this quick movement the sheath-like labium, its tip covered with chemo- and mechanoreceptors, is pressed to the surface
 of the food source; the pointed tips of the mandibular  stylets extend to cut into the prey and anchor it to the predator; and the maxillary stylets extend into the prey, injecting venom.
 Once venom injection has induced paralysis or death,  feeding typically occurs over  a period of several  minutes to several hours. During this process the stylets may extend deep
 into the prey, distributing liquefying venom, macerating the prey, and sucking up fluid food.  Some giant water bugs (Belostomatidae) grow to be very large(10–12 cm) and have been
 recorded killing vertebrates including frogs, turtles, snakes and birds."

The term "extra-oral digestion" (EOD) refers to the application of chemicals to allow for predigestion (liquefying, etc.) before ingestion of the  resultant "slurry".
  The various mixtures of
"salivas" and "venoms" are not consistent between all members of the true bugs but are related and develop with the dietary needs of each species. Depending on species, some of
these elements cause paralysis or death; immobilizing  prey allow for the other  gland contents to break down the prey for ingestion. There's a lot going with our insect neighbors. Here
 are a few characteristics to help tell the species apart.
 

from Goforth 2009:
"The Abedus doesn’t have the long respiratory siphons you find in some water bugs. These are called air straps, the shorter of  the two types of respiratory appendages
 in the belostomatids. This bug is broadly rounded, particularly in the back. The other two American  genera of giant water bugs have pointed tips at the end of their abdomens. So, the
 combination of the rounded back end and short air straps lets you know that this waterbug belongs to the genus Abedus.
  This bug has air straps and not the long respiratory siphon.
Belostoma is more rounded overall than Lethocerus as well, but it is also pointed in the back. You can tell Belostoma apart from Lethocerus easily by looking at the  size of the bug and
the presence of air straps. Belostoma is easy to distinguish from Abedus simply by looking at the shape of the back end--pointed in Belostoma and rounded in Abedus. Lethocerus is very
different from the Belostoma and Abedus. There's a long respiratory siphon at the back end. They do look quite a bit shorter when they’re retracted, so the difference between the respiratory
 siphon of this bug and the air straps of Abedus should be immediately obvious. The shape of Lethocerus is also distinctive. This bug is robust and strong, has huge raptorial forelegs and
 is also pointed at the back end. Lethocerus species are BIG bugs."

So, we have at least 2 species of giant water bugs turning up at our pond life programs. The biggest ones are Lethocerids (including the one I found in the spider's web). I had started looking
mostly for descriptions of the saliva/venom because I often wondered they hurt so much if they bite and what they are putting into us when they bite. I found all of this other material during my
search.


06/11/2023 Brazos Bend State Park. As I was beginning to lead the Creekfield Hike that morning, I was talking to our park guests when I looked over towards the bathroom 
doors. Sometimes, I take the group around  the outside of the Nature Center to look for whatever critters might be on the walls. That morning, I was on the sidewalk when I saw
this very large insect near the door to the Breezeway. It was a Swamp Darner (Epiaeschna heros), one of the largest dragonflies in the U.S.  After a brief online search, I found
that this species deposits its eggs by drilling  into wood. This is unlike many other dragonflies, which lay their eggs on water. The SD stayed there while we got closer and 
took pictures, and was still there about an hour later when I got a few more pictures.

       

August 11, 2019  One of the most enjoyable programs we offer at BBSP is the "Pond Life Program". We set up a "reservoir" table that can hold water, and a flat table, on one of the
trails.   We put water in the reservoir, then use nets to collect samples of the aquatic vegetation. We place samples on the flat table, and dig through them with tweezers to see what
we find. We put the live animals into the water for display and description. After the program, many of the animals go into our display aquarium in the Nature Center. Park visitors are
welcome to watch, or even assist with some loaner tweezers. Today was quite productive. In the larger image, we can see small fish, freshwater shrimp, crawfish, snails, water bugs,
and water scorpions (which are also "true bugs") I've labeled various types of organisms we found during that Pond Life Program.

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But the prize, in my opinion, was the capture of these giant water bugs. I've always known they were impressive predators, and it was a treat to see
them. I took all of these pictures with my phone. When I'm helping do the program, I don't have time to handle my usual cameras. But I had to get
some pictures of these, showing details of the top and bottom views while I held the bug.

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December 05, 2004
  There are often interesting things to see in the aquarium at the NC. Today, on of the Giant Water bugs had climbed out of the
water. Again, those eyes are amazing...and, that front pair of mighty raptorial arms.  (note: I'm uploading these images 10/11/2024. I was previously
 reluctant to share images I've gotten from the tank because they aren't "in nature". Now, 20 years later, I know that sometimes there is no other
option for seeing some of these creatures doing anything, except for watching them inside an aquarium. )

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November 14, 2004  There are often interesting things to see in the aquarium at the NC. Today, multiple Giant Water bugs, with one that was probably
eating one of the Water Scorpions. It was holding onto one its front raptorial legs, and eventually a few of its other ones.  (note: I'm uploading these
images 10/11/2024. I was previously reluctant to share images I've gotten from the tank because they aren't "in nature". Now, 20 years later, I know that
sometimes there is no other option for seeing some of these creatures doing anything, except for watching them inside an aquarium. )

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September 19, 2004   Today, I took was able to get just on good picture of this Giant Water Bug in the Nature Center. Getting clear images by shooting
through the glass is often difficult, but here's one. Look at those eyes! (note: I'm uploading these images 10/11/2024. I was previously reluctant to share images I've gotten
from the tank because they aren't "in nature". Now, 20 years later, I know that sometimes there is no other option for seeing some of these creatures doing
 anything, except for watching them inside an aquarium. )

            


August 29, 2004  There is a big aquarium in the Nature Center.  It is usually stocked with animal life that we catch inside the park. Usually, there are interesting things
to see in the aquarium. Today, I took was able to get some good pictures of this Giant Water Bug. (note: I'm uploading these images 10/11/2024. I was previously
reluctant to share images I've gotten from the tank because they aren't "in nature". Now, 20 years later, I know that sometimes there is no other option for seeing
some of these creatures doing anything, except for watching them inside an aquarium. )

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August 02, 2003  l admit it. I like some science-fiction. I like some science-fiction movies, I like some movies with monsters, and some movies with alien creatures that will come up upon 
their unsuspecting prey and rip their head off.
But, you know what's really, really cool?  This kind of thing is happening on Earth, in real life, all around me! And, unless you (my internet guest 
who's reading this) live somewhere like Antarctica, it's happening all around you, too!  To see it, all you need to do is stop thinking all the time, take a mental rest, and just look around.

The RICKUBISCAM today is a picture of something that caught my attention when it moved just at the edge of my peripheral vision. At first glance, it looks like two dragonflies attempting to 
make more little dragonflies. Then we can see that they appear to be two different species of dragonlfly.

Then, if we take a closer look (see THIS CAN'T BE GOOD, below), we can see that the brown dragonfly (According to Park Naturalist David Heinicke, the Green Dragonfly is a female 
Eastern Pondhawk-Erthemis simplicicollis; the deceased one is a female Widow Skimmer - Libellua lucuosa. Thanks, David.) is missing its head and part of its thorax. A little bit closer view
(see CONCEALED WEAPON, below) shows the mandibles slipping from their wonderfully complex and mechanical sheath and grinding away at the hapless victim. To see two short clips 
of the mandibles in action click on the following links clip one (flv video 647kb, or see EATING 1, below); clip two (flv video 658kb, or see EATING 2, below). (Sorry about the movement of the
camera. I couldn't set up a tripod.)   Now we can see that this is the outcome of another intricate, high-speed dogfight between two dragonflies. Those bozos! Can't they cut that stuff out and 
go after deerflies and mosquitos instead? There must be plenty of those to go around! However, when you get to this level of existence, you have prey animals, and then you have animals 
that you have to compete with for that prey, and you have animals that might think YOU are prey. A dragonfly eating another is not only giving itself more food by eliminating competition; it's 
getting a meal directly while it's eliminating the competition! Not to mention that it's also eliminating a potential attacker. Wait, I mentioned it.  Oh, well.
 


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               GHASTLY EMBRACE                                               THIS CAN'T BE GOOD                                      CONCEALED WEAPON  

              
              DRAGONFLY EATING 1                                                  DRAGONFLY EATING2

July 27, 2003  This is how I think it happened: It glided silently through the jungle that was its hunting ground. Among its fellow creatures, it was the apex predator, and it moved its 
delicate, sleek length through the clearings and passages of its domain.  From time to time, lesser creatures would become visible, and many of them were attacked and killed in seconds,
and then chewed to pulp and eaten. Many times, this fearsome predator wouldn't even bother to stop moving as it ate its helpless victims. As a flier, it had no peer, and had evolved a 
fantastic behavior that would allow it to fly at prey (or challenge others of its kind) by flying in a manner that--although it was moving at a terrific speed--would allow it appear immobile to its
intended target.  Since it appeared to be a stationary object, its intended target would ignore it; until it was too late, and then another victim could die. The predator was a Dragonfly--a Green
Darner. Its huge compound eyes covered its entire head, and it could see in almost every direction simultaneously.
As it flew through a stand of tall weeds (grass is common for what 
happens next)--perhaps swooping for prey--there was a sudden movement from above and behind.  The dragonfly may have felt a loud buzz, and suddenly it was hit from above, in the thorax,
right between the wings. Immediately after, a sharp spike was thrust into the dragonfly's beautiful hard shell, and it lost control of its wings. It hit the ground, and was already helpless as its 
bodily fluids began to be pulped and sucked out through a single hole in its exoskeleton. The dragonfly was doomed.
The Dragonfly had been attacked by a Robber Fly. These are large 
insects that are *also* apex predators. They are also deadly and efficient hunters. However, where the Dragonfly relies on strength and speed, and can fly and attack in the open, the Robber
Fly will often perch on a good spot (like a tall blade of grass) and just watch. When something interesting passes, the Robber Fly launches its surprise attack, and hits its prey in flight. Where
the Dragonfly chews its prey to pulp with its mandibles, the Robber Fly uses piercing mouthparts to suck out juices.
The image below (IN ITS CLUTCHES, below) shows the outcome of the 
hunt. I've seen Robber Flies hunting, just as I've described. Often, they just fall to the ground (although it seems they try to brake with their wings) with their prey. I have been trying to get some
good close-ups of this for at least a year, but the insects have always flown off.  This morning, however, one of the volunteers (cool, Allen!) just walked into the visitor center with the Dragonfly
and its killer.  The Robber Fly was attached, eating, and would NOT move.  I snapped a few pictures.  The pair of insects was then left outside, where I was able to get some better close-ups.
  The three pictures below are three views of the same image. The fingers are mine, and you can see the scale. I've cropped in to show the mouthparts where it pierces the thorax.  Later in 
the day, the Dragonfly was still in the garden and was intact, though reasonably empty. Ants had found the carcass, though (lots of ants...FIRE ants. No more pictures. Sorry.). And the Robber
Fly had gone; perhaps to attack another Dragonfly, perhaps to be eaten BY a Dragonfly.
 

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                      IN ITS CLUTCHES                                          LLET ME EAT IN PEACE                                            KILLER AND VICTIM                                               NEAT EATER


If you'd like to know more about the park follow these links:

Brazos Bend State Park   The main page.

Brazos Bend State Park Volunteer's Page  The volunteer's main page.
 

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