Insect stages ~ Some larvae, nymphs and adult insects that live in freshwater

In pond water you will come across many insects, often perfectly adapted to the aquatic environment. Some species are entirely aquatic, whereas other insects only live in the water during their larval stages or as nymphs. When insects undergo a metamorphosis we call the immature form larva. When they gradually transform via moults into the adult form the young stages are called nymphs. This pages gives a simple overview of these stages and some of the adult forms. There are no Micscape links yet, articles welcomed!

Note on size: Many aquatic insects and their immature stages can vary in size from a few mm to 3cm or more depending on e.g. maturity and species, so sizes have been omitted for most groups. The shape and general features are a more reliable guide to a group than size.



key features

Alderfly nymph

one tail, long filaments along the abdomen

Caddisfly larva

most species build a cylindrical case for protection, each species makes a distinct case from different material

Stonefly nymph

two jointed tails

Mayfly nymph

three jointed tails, leaf-like (or other shaped) 'gills' on its sides

Damselfly nymph

three leaf-like tail appendages (gills), bizarre extendable jaws

Dragonfly nymph

robust, no tail appendages, bizarre extendable jaws

Water bug

no jaws, like all water bugs they possess a tube-like beak, the nymphs don't have wings, 
Some common forms: Backswimmer, water boatman. On the water surface: Pond skater

Water-beetle larva

strong jaws, long segmented body, short legs

Water beetle adult

strong jaws, tough shield, many water beetles are fierce predators


the grey spring-tail (the most primitive insect group) Podura aquatica lives on the surface of the water, often in large numbers, 0.5-2.5mm
Visit the Postal Microscopical Society (UK) Springtail Group site for overview and projects

Mosquito larva

with a long slender body, often moves in S-shaped curves,

Dronefly larva

this so called rat-tailed maggot has a long tubed tail for breathing

Other Arthropods that are not insects

Go to arthropods overview: e.g. ostracods, copepods, water fleas, mites etc.



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Collecting tips



This page with links hopefully gives a useful overview, but it's neither a formal identification guide nor comprehensive.

An Introduction to Microscopy

Comments to the compilers Wim van Egmond and Dave Walker are welcomed.

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