WARNING! This is not a professional website! I am NOT an expert. Do NOT believe everything on this site.

Last Updated: 4/6/08

Alderflies, Dobsonflies, and Fishflies (Megaloptera)
Beetles - water beetles, waterlily leaf beetles, predaceous diving beetles, whirligig beetles (Coleoptera)
Caddisflies (Trichoptera)
Dragonflies and Damselflies (Odonata)

Please note that Robyn's main aquatic insect index has moved to bugs.htm as this page became too large.

A complete list of all the insect photos I have taken from my ponds can be seen on my pond pictures page.

I plan to divide up the insect pages and expand on them sometime in the next few years.

Megaloptera include alderflies, Dobsonflies, and fishflies. These larvae are all predators. Their appendages are small but there are a LOT of them. Most are nocturnal.

Alderflies

Alderfly larvae have thick brown skin, grow to about an inch long, have a single pointy tail, and tend to hide out.

Dobsonflies

Here are two photos of a female dobsonfly that Ken sent me on 6/21/04. In the second photo, she is threatening him!:
Dobsonfly
Dobsonfly

Dobsonfly larvae are called hellgrammites (they look like they are from hell?) and grow up to 3 inches long. The adults grow up to 2.7 inches, and the male has inch long curved mandibles. Adult males have jaws half the length of their body. Females' jaws are smaller but can bite. Hellgrammites live for up to 2 or 3 years in the water while the adults live only a few days. Hellgrammites are often used for bait. The larvae use their killer jaws to capture and eat insects and small animals. The Eastern Dobsonfly is Corydalus cornutus.

Drawings of a larval Dobson fly can be seen at this water bug site under hellgrammite.

Drawings of a larval and adult dobson fly can be seen at this site.

Fishflies

Fishfly larvae, Chauloides species, look like Dobson fly larvae, but only grow to about an inch long. Larvae eat aquatic insects by seizing them in their jaws. Nocturnal adults look like a cross between a cicada and a moth. They are poor flyers and easy to catch.

Coleoptera, or beetles, have a few species with aquatic larvae which are very predatory. Diving beetles and whirligigs are common adult beetles which stick around the pond. Because there are 280,000+ species of beetle, most people know what an adult beetle looks like. Few people, however, would identify dry-land worm-like creatures or what look like aquatic centipedes as beetle larvae. Most beetle larvae can be identified separately from other insects because their body is often covered in a much thicker, black plating and some species have long filaments off the sides of their bodies. One species of larvae looks like a caddisfly larvae with a suit of armor. Most range from 0.3 to 1 inch long but there is a large range of sizes. Likewise, their food preferences vary from plant to animal to detritus. Some kinds of water beetles follow.

Crawling water beetles:

Crawling water beetles crawl around eating plants as larvae but adults eat animals as well. Most of the 50 North American species range from 0.2 to 0.4 inches long. The larvae usually look like aquatic centipedes with very long filaments.

Waterlily leaf beetles:

The waterlily leaf or Donacia beetles are predators of aquatic plants. Mostly they eat water lilies but may attack skunk cabbage, pickerel weed, and other plants. There are at least 36 species. They have a glossy body of black with green or yellow shiny specks. In the summer, adult females put o's in lily leaves and deposit their eggs through the hole under the waterlily leaf. Larvae make silk nests under the leaves. It takes about 10 months for an egg to result in an adult. Eggs and larvae can be wiped off leaves. If the infestation is bad, plants can be treated with insecticides outside of the pond and returned after a good rinsing. Remove dead vegetation around the pond to reduce the population of overwintering adults. Adults are a quarter to half an inch long.

Predaceous diving beetles:

Predaceous diving beetles can be found both as larvae and adults in ponds. Adults grow up to 1.5 inches depending on species while some larvae can grow to 3 inches. There are at least 500 species in North America alone.

The larvae are called water tigers and have sharp pincers to eat tadpoles, their siblings, and other critters. Adults eat bugs, fish, tadpoles, each other, and frogs. They bring air bubbles underwater with them to breathe. In some species, oxygen from the water can diffuse into the bubble and extend the time a beetle can stay underwater. A chemical they produce is spread over the body to reduce water resistance (making it easier to swim), to repel predators (they taste bad), and to keep fungi and bacteria from attacking them. Adults spend a lot of time flying around and show up at night lights. During the winter, they stay in the pond. In China, some people eat them.

The diving beetle (Dytiscus) has two dagger-shaped mandibles that it impales into its prey. Through these, the beetles pump in toxins and enzymes that render the insides of the victim into liquid that the beetle can suck back for food.

On 5/27/06, I noticed our pool cover was full of beetle larvae, maybe diving beetles. I am mentioning it because I noticed that some of the larvae would actually walk out of the water. I did not know they could do that. Whether that is normal, or they were doing it because of poor water quality, low oxygen, or lack of food sources, I do not know. Many were shriveled up around the edge of the cover though.

Drawings of a larval and an adult predaceous diving beetle can be seen at this water bug site.

Whirligig beetles:

Whirligig beetles, Dineutus species, are some of the funniest insects to show up at my ponds. The adults act like they have had too much too drink and spin around in the water. The 0.5 to 1 inch adults are scavengers and can see above and below water at the same time. Their front legs are long. Adults eat dead plants and animals and insects. The larvae, on the other hand, eat whatever animals they can catch and have more noticeable filaments than legs. Larvae are 0.8 to 1 inches long and crawl along the bottom. Larvae may eat insects, snails, and mites.
Drawings of a larval and an adult whirligig beetle can be seen at this water bug site.

Becky sent this link on 4/3/06:
Whiligig Beetle - on the Australian Buglopedia site.

Miscellaneous beetles:

A few other species with aquatic larvae are the water scavenger beetles (160 species, 0.3 to 1.5 inches long), dryopids (25 species, 0.5 inches), elmids (75 species, 0.3 inches), leaf beetles (0.1 inches), and tiger beetles (0.5 inches). Some eat animals, and some eat plants.

Caddisflies, or Trichoptera, are some of the most common species you will find in your pond. Turn over a rock in your waterfall or stream. If there are worm-like critters wiggling about or creatures inside little homes made of rock and debris, they are caddisflies. Caddisfly adults are about 0.5 inches long while larvae are 0.6 to 1.5 inches long. They use two tail hooks to anchor to their homes of leaves, sand, twigs, and other debris. They eat plants and animals that pass by in streams as well as moss and algae, depending on the species. After being a larvae for quite a time, they change into pupae for about two weeks and then adults for a month. The nocturnal adults look like moths. There are 750+ North American species. Each species has adiffering physical characteristic and makes their portable home slightly differently. A few species do not make homes and are free-living. Homes can look like a bunch of twigs, a cocoon, a tunnel of sand, a cornucopia, or many other designs.

Cheryl informed me that caddisflies are the only aquatic insect to spin silk. They use it to make little webs to trap detritus and for cocoons.

One caddisfly is Betten's silverstreak caddisfly, Grammotaulius bettenii. It grows from a quarter of an inch to almost an inch. Larvae eat algae and debris. Their tubes are made of dead leaves and twigs and saliva.

Drawings of a larval and adult caddisfly can be seen at this water bug site.

Drawings of a larval and adult caddisfly can be seen at this site.

Dragonflies and Damselflies:

Odonata is the order containing the very visible dragonflies and damselflies which frequent ponds. About 307-550 species of dragonflies and damselflies live in North America depending on which source you believe.

Telling Adults Apart:
Damselflies differ from dragonflies in that they are smaller and very slender. Also, when resting, dragonflies keep their wings open and damselflies keep theirs along their backs. Adults, aside from females laying eggs, pose no threat and bring the pond area alive.

Telling Nymphs (Larvae) Apart:
Damselfly nymphs are more slender than dragonflies and have three gills on their rear, unlike dragonfly nymphs. Both dragonfly and damselfly nymphs are often covered in a growth of algae for camouflage. Dragonfly larvae are short and fat while damselfly larvae are smaller and skinny (long). Often, ponders only realize that they had nymphs in their pond when they discover the cast off outer skins that nymphs leave behind when they leave the water as adults.

A link on telling dragonflies from damselflies can be found at this Defender's of Wildlife site.

Adult Behavior and Breeding:

Adult dragonflies and damselflies fly around and hang out around ponds. A male and female often fly around and sit together while attached during mating. Females lay eggs in the stems of water plants (they cut holes in the stems) throughout summer.

Dragonflies:

Here is a photo of an empty exoskeleton of a dragonfly after it has left. They crawl out of the water at that time. Judi sent this photo on 7/4/06 for identification.

Because they eat lots of mosquitoes as adults, dragonflies are also called Mosquito Hawks. Dragonflies are large insects, growing 2 to 3 inches with 2 to 4 inch wingspans. The 1 to 2.5 inch dragonfly nymphs are camouflaged and look like adults except they are brown, have massive jaws, lack wings, and usually are less slender in the rear.

After hatching, the nymphs stay in the water for three months to five years, depending on the species. While there, they eat whatever they can catch and are thus known to some as menaces to ponds (whereas adults are a blessing, eating mosquitoes). Nymphs whole heartedly consume insects, worms, mollusks, fry, small fish, tadpoles, frogs, and more. Hiding in mud, among rocks, and other places; they wait for prey to come near and then pounce. Ponds with lots of nymphs rarely have fry that survive to adulthood. I saw one two inch nymph with a three inch frog clasped in its fierce jaws. I freed the frog who otherwise (and may still have) would have been eaten. If you wish to control these predators, you have to hand pick them out of the water. Also, large fish will eat nymphs (but large fish may eat small fish too). Adults eat most flying insects including mosquitoes.

Dragonfly species:
The green darner (Anax junius, 3 inches long) is the most common species of dragonfly with belted skimmers (Macromia) also being common. When a green darner shows up at my pond, it really stands out because it is one of the biggest and fastest dragonflies. It is somewhat scary! The widow (Libellula luctuosa, 2 inches) is easy to identify by its wings being half black and half clear (on the end). The twelve-spot skimmer (Libellula pulchella, 2 inches) is also black and white but with black and white alternating to give three white spots (two on the front wings) and three black spots. These dragonfly species are all visitors to my ponds but by far, most dragonflies I see are swift long- winged skimmers, also called blue dashers (Pachydiplax longipennis, 1.5 inches). They are smaller and have short, wide, blue bodies.

Odonate Links:

• Dragonfly page based in Texas which shows real photos of the species present in that area.
  
• Site with drawings of larval and adult dragonflies at this water bug site.
  
• A Guide to the Adult Damselflies & Dragonflies of the Ottawa District - provides some interesting dragonfly information.
  
• British Dragonfly Society - information including an article on digging a pond for dragonflies.
  
• The Odonata Information Network - more information on dragonflies and damselflies.
  
• California Dragonflies & Damselflies - information on those in CA.
  
• The North American Dragonfly Migrator Project.
  
• Texas Odonata Central.
  
• Dragonfl y drawing.
  
• Dragonfly nymph drawings and information - part of Buglopedia in Australia

There is a really good book on dragonflies and photos for identifying them: Dragonflies Through Binoculars: A Field Guide to Dragonflies of North America by Sidney W. Dunkle, Oxford University Press, 2000.

Photos of my dragonflies:

A photo of some nymphs that belong to Leej (not mine nor my photo) are above.
A photo of one of my newly-adult dragonflies is at the top of this page.
A photo of an adult dragonfly (probably a blue dasher) is at the top of my insect index page.
Here is a photo of a female common whitetail or Libellula lydia which is similar to the female 12-spotted skimmer, Libellula pulchella, except the whitetail has diagonal white dashes on her abdomen. This female was sunning by my 1800 gallon pond on 7/7/02.

On 5/29/04, I found three dead dragonflies and photographed them:
All three dragonflies - the order of them left to right is below in the close-ups
Male twelve-spotted skimmer - Libellula pulchella; he was sucked dry, probably by a spider (the other two were intact); he has white spots on his wings but they do not show up to well in this photo
Male blue dasher - Pachydiplax longipennis, with a live cicada; he was blue but the photo makes him seem almost black
Female twelve-spotted skimmer - Libellula pulchella, with a live cicada; she has no white spots but the photo makes it look like she might

Dragonfly - this dragonfly has just come out of its empty exoskeleton which is also in the photo. I think it is some sort of darner but am not sure because it is kind of plain. This was taken 8/31/06.
Dragonfly - similar to the last photo, 8/31/06.
Dragonfly - similar to the last photo, 8/31/06.

On 4/1/08, I cleaned out my 153 gallon pond and found three dragonfly larvae. Here is a photo of the largest one.
Dragonfly nymph waiting in one of the kiddie pools.

Damselflies:

Adults are 1 to 2 inches long and very slender. You almost cannot tell they are there. Common bluets are a common species of damselfly. The short-stalked damselfly, Argia species, grows to 1.5 inches. Damselflies are also called dancers because they do not sit still for long.

Damselfly nymphs are slender and have three gills on their rear. They are only about 0.8 inches long. They eat the same foods as dragonfly nymphs but smaller in size. They are less likely to go for fish and frogs, sticking instead to small insects and crustaceans. Adults eat small insects.

There is a site with drawings of larval and adult damselflies at this water bug site.

See the list of dragonfly sites above as they usually have damselfly information and photos too.

Here is a photo of one of the damselflies that visited by my 153 gallon pond. The photo is too fuzzy to identify the species.

Here is a damselfly that I found in the basement next to my 20 gallon indoor tub pond on 1/1/05.

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