The behaviour of recently-hatched caddis larvae from temporary water bodies in the British Isles

Caddisflies use four basic methods to ensure that newly-hatched larvae become aquatic insects. One is to lay the eggs underwater so larvae can start a free life immediately after hatching. Another method is to lay the eggs above water and the hatched larvae fall or wriggle into the water. Caddisflies from waters that dry out in summer often have a female diapause gradually becoming sexually mature and often do not lay their clutches until late summer or autumn, when rising water levels flood the eggs. The hatched larvae develop into pupae by March-May, from which adult caddisflies hatch again emergence beginning in spring. Some caddisflies from waters that dry out lay in summer and those eggs hatch soon after laying so it is as a larva that they survive the dry period.