Field Guide

Aquatic Invertebrates

Showing 1 - 10 of 47 results
Media
Photo of backswimmer, side view
Species Types
Scientific Name
About 32 North American species in the family Notonectidae
Description
Sometimes called “water bees” or “water wasps,” backswimmers are predaceous and can deliver a painful bite if mishandled. True to their name, they swim belly-up, and their backs are keeled like a boat, which makes back-swimming easier.
Media
Photo of a giant water bug
Species Types
Scientific Name
Species in the genera Abedus, Belostoma, and Lethocerus
Description
Giant water bugs are huge aquatic insects that frequently fly around electric lights at night. They are infamous for the painful bite they can deliver, but fish, birds — and some people — find them tasty!
Media
Photo of a dragonfly larva resting on a stone.
Species Types
Scientific Name
Species in the suborder Anisoptera
Description
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.
Media
Photo of a pink planarian on a rock.
Species Types
Scientific Name
Dugesia, Planaria, and other genera
Description
Unlike their parasitic cousins in the flatworm group, turbellarians, or planarians, are tiny carnivores or detritus-eaters that glide smoothly across submerged leaves and other objects.
Media
Gray, speckled, translucent gelatinous blob cut in half to show structure
Species Types
Scientific Name
Freshwater species in the phylum Bryozoa
Description
Bryozoans are tiny, filter-feeding invertebrates. They create colonies that can be mossy, branching, or round and jellylike.
Media
Photo of a mayfly naiad crawling on rock underwater
Species Types
Scientific Name
There are hundreds of species in North America.
Description
Mayfly larvae, or nymphs, live from months to years under water, breathing through gills, and the adults fly around in the air, mating, living for only a day or two.
Media
Photo of a stonefly naiad clinging to a rock underwater
Species Types
Scientific Name
There are hundreds of species in North America
Description
Stonefly larvae are aquatic and somewhat resemble the larvae of mayflies and damselflies. Their presence usually indicates good water quality.
Media
Photo of a damselfly nymph on rocks in an aquarium.
Species Types
Scientific Name
Species in the suborder Zygoptera
Description
Damselfly larvae are narrow-bodied aquatic insects with large eyes, six thin legs, and three paddle-shaped, tail-like gills at the hind end.
Media
Photo of hellgrammite
Species Types
Scientific Name
Corydalus cornutus
Description
Hellgrammites are the aquatic larval form of eastern dobsonflies. They are fiercely predaceous and look a little like centipedes. Anglers often use them as bait.
Media
Photo of a horsehair worm in an aquarium
Species Types
Scientific Name
About 350 species scientifically described.
Description
Adult horsehair worms can be nearly 3 feet long and live in water. They are practically featureless, smooth, aquatic worms that writhe into knots and curls.
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.