Caddisfly larva (trichoptera)

There are over 200 different species of caddisflies in the UK. Although as adults they are flies, they live most of their lives as larvae in the pond, only emerging as adult flies for a couple of weeks at the end of their lives.

When they are larvae, like caterpillars in the butterfly life cycle, they live in the pond. These amazing creatures make a case around themselves for camouflage and protection. It's not a full cocoon, but is open at the end so that they can continue to feed and move about. They use whatever they can find around them to make their case, so in a stony river, it would be made of stone, whereas in a woodland pond it would be made of dead wood and leaves. The larvae stick all the pieces together using a glue which they make themselves, a bit like a spider's web. As they grow, they find new material to add to the front of their case. If you look closely at the photo above, you can see the caddisfly larva's head, antennae and front legs peeping out of the front of the case.

After about a year, the larvae make the case into a full cocoon by the water's edge and then transform into a flies. The caddisflies only live for a couple of weeks, enough time to mate and lay eggs in vegetation just above the water's edge.

Caddis fly larvae can be found in most clean ponds and rivers. They eat tiny bits of dead vegetation, any rotting organic matter. The larvae are the favourite food of dippers, other birds, fish and newts. Look out for them next time you are at a pond. They really are amazing creatures!