Nanostructured underwater adhesive tape
Caddisflies (order Trichoptera) are closely related to terrestrial moths (order Lepidoptera), including the domesticated sillkworm moth. In contrast to moths that spend their entire life on dry land, caddisflies spend the majority of their lifecycle in freshwater rivers, lakes, and streams. Larva of both orders produce silk. Terrestrial moths spin familiar cocoons, whereas caddisfly larva use their silk like adhesive tape (above B) to build elaborate composite structures with materials gathered from their underwater environment. Some species are mobile foragers that tape together rocks, sticks, or leaves into cases around their soft larval bodies (A). Other species build stationary retreats with rocks or leaves and spin fishing nets to capture food from the stream (below B). Others are free living and only use their silk to spin a cocoon with a rocky dome just before pupation (C). The similarities to terrestrial silks raises an interesting question, what molecular adaptations of their silk were necessary for caddisflies to enter the aquatic environment?