Field Guide

Aquatic Invertebrates

Showing 1 - 9 of 9 results
Photo of caddisfly larva with case made of detritus
Caddisfly Larvae
About 1,500 species in North America north of Mexico
The aquatic larvae of caddisflies are famous for building portable, protective cases out of local materials, including grains of sand, bits of leaves and twigs, and other debris. The adults are mothlike.
Photograph of several mosquito larvae resting at water surface
Mosquito Larvae
There are about 50 species of mosquitoes in our state.
The larvae of mosquitoes, often called “wrigglers,” have a large head and thorax and a narrow, wormlike abdomen; they typically hang just below the water surface. When disturbed, they wriggle downward.
Photo of a spotted fishing spider perched on the water's surface amid floating duckweed plants
Aquatic Spiders
Dolomedes spp., Tetragnatha spp., and others
A variety of spiders are adapted for live on and around water. Many of these are called fishing spiders. Several have the ability to run across the water’s surface. Some build webs, others do not.
Photo of a single water strider
Water Striders
Aquarius remigis; also species in the genus Gerris
Water striders are eye-catching. Water-repellant hairs on the hind and middle legs allow these nimble insects to skate on the surface of the water.
Photo of two water penny beetles clinging to a wet rock.
Water Penny Beetle Larvae
Beetles in the family Psephenidae
Water penny beetle larvae are truly nifty aquatic invertebrates that bring out the child in all of us. Some of them really do look like pennies!
Photo of a whirligig beetle viewed from above
Whirligig Beetles
Species in the beetle family Gyrinidae
Groups of whirligig beetles swim on the water surface in quick, random patterns, searching for food. They have two pairs of eyes — one pair above water, one pair below — to help them quickly and accurately capture their prey.
Photo of a predaceous diving beetle
Predaceous Diving Beetles (Water Tigers)
Species in the beetle family Dytiscidae
Like many aquatic insects, these large oval beetles prey voraciously on other aquatic organisms. Excellent swimmers, they fly well, too, and are often attracted to lights.
Photo of a collared water scavenger beetle showing back.
Water Scavenger Beetles
Beetles in the family Hydrophilidae
Water scavenger beetles are a mostly aquatic family. They are similar to predaceous diving beetles, but unlike them many have a distinctive spine running down the center of their bellies.
Water boatman viewed from above
Water Boatmen
About 125 species in North America in the family Corixidae
Water boatmen are one of the few aquatic true bugs that are not predatory and do not bite people. Instead, they suck juices from algae and detritus. Only a few types eat other small aquatic creatures.
See Also

About Aquatic Invertebrates in Missouri

Missouri's streams, lakes, and other aquatic habitats hold thousands of kinds of invertebrates — worms, freshwater mussels, snails, crayfish, insects, and other animals without backbones. These creatures are vital links in the aquatic food chain, and their presence and numbers tell us a lot about water quality.