Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 10 results
Photo of a dragonfly larva resting on a stone.
Dragonfly Larvae
Species in the suborder Anisoptera
Dragonfly larvae are aquatic insects with large eyes, six legs, and an oval or rounded segmented abdomen. The lower jaws are scooplike and cover much of the lower part of the head.
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.
Photo of crane fly larva
Crane Fly Larvae
There are over 500 species of crane flies in North America.
Crane fly larvae are tan or gray grubs that live in aquatic habitats or in moist places on the ground. The harmless adults resemble huge mosquitoes.
Photo of an alderfly larva among rocks and gravel in an aquarium.
Alderfly Larvae
Sialis spp.
Alderfly larvae look a lot like their cousins the fishflies, but instead of having pairs of fleshy tails, they have only a single tail pointing straight back.
Photo of a damselfly nymph on rocks in an aquarium.
Damselfly Larvae
Species in the suborder Zygoptera
Damselfly larvae are narrow-bodied aquatic insects with large eyes, six thin legs, and three paddle-shaped, tail-like gills at the hind end.
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.
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.
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.