Best time to see: all year
Key facts
Moth-like insects forming a large group known as Trichoptera, mostly associated with fresh water
The young play an important role in freshwater ecology, keeping the water clean by feeding on leaves and other debris
Britain has about 200 species
Recognition
Adults have four wings, folded tent-like over the abdomen when at rest, and long antennae
The larvae live in fresh water, some using silk to bind together materials such as twigs or sand to form a protective case
Weak fliers, on the wing mainly in late afternoon and at night; up to 65mm wingspan and 20mm body
Lifecycle
The lifecycle is annual, the larvae staying under water to feed through autumn and winter before entering the pupal stage
They spin a cocoon within their case to pupate and emerge from the water in late spring or summer
Adults only last a few weeks, feeding little if at all, mated females laying eggs on plants near to the water surface
© Tony Gunton