Aquatic entomology is the study
insects that inhabit freshwater for at least part
of their lives. Usually it is the larval
(immature) or nymphal stage that inhabits
freshwater streams or lakes.
Common freshwater insects are dragonflies
(Trichoptera) and mayflies
(Ephemeroptera). Large larvae of these insects are
sometimes used as bait by fishermen and replicas
of the adult insects are used by "fly" fishermen
Mayflies [pictures] are the most
primitive of the aquatic insects. Larvae live in
freshwater streams and ponds feeding on algae and
detritus. Adults emerge, often in large numbers,
but only live a short time.
Dragonfly and damselfly adults [pictures] are familiar to
most people but the larvae may not be. Larvae live
in freshwater while adults are generally found
near water. Both larvae and adults are predators.
Stonefly adults [pictures] are medium-size,
drab-colored insects with the wings folded flat
across the back. Larvae live in freshwater where
they are predatory but also feed on plant
Caddisfly adults [pictures] resemble moths and
are the most advanced of the aquatic insects.
Caddisfly larvae are caterpillar-like and often
live within a case made of sand grains or plant
material. Some larvae are free-living predators.