Caddisflies are insects that spend the first stages of their lives under water and then emerge as adults to fly in air. There are many species world-wide.
Many caddis larvae build cases in which they live, made of small stones, sand grains, even twigs and pieces of leaf, all held together by silk that the larvae produce. Some move around taking their cases with them. Others are free living, but may build “houses” of small stones to which they can retreat.
This free living caddisfly’s scientific name is Hydrobiosis and it grows up to 2 cm long.
These types of caddis are found in a range of water and stream types in moderate-to-fast flowing water, amongst or on stony substrates. Several species are also found in lowland, soft-bottomed streams, and often form one of the groups in these habitats more sensitive to pollution and water quality.
The caddisfly makes its shelter out of stones and hides there until it has grown wings. Then it climbs out of the stream and flies away to find somewhere to lay its eggs.
Did you know? Adult caddisflies commonly fly at night and are attracted to ultra-violet light.
Some species of caddis make small nets of silk that attach to the bottom of the stream so they can catch small animals and plants drifting in the water.
Below is a picture of an adult caddisfly.