The larvae of the caddisfly may not look particularly special, but this insect species is an underwater architect, engineer and materials specialist.
The soft-bodied insect larvae lives in fast-moving streams. To protect itself from predators as well as the debris speeding through the water, the larvae carefully selects pebbles that it tapes together — yes, tapes — with a special silk that can stick to the pebbles despite being underwater.
According to KQED Science, "Though its mechanism isn’t fully understood, the glue part of caddisfly tape forms highly complex bonds, both chemical and physical, with whatever it’s sticking to. As these bonds form, they displace the water where the tape meets the stone, allowing the two substances to stick together."
The waterproof, elastic material bonds the pebbles together into a shape that the caddisfly can drag around and feel safe from danger. However, our fascination with the caddisfly goes deeper than an amazing little insect that builds a house out of tiny stones and silk. The unassuming caddisfly might help us come up with a new medical material.
We humans have come up with waterproof adhesives, where the bond is formed on dry land and holds up under water. But we've yet to develop a material that can be bonded to a surface while underwater. Bioengineers are searching for it with the caddisfly's miracle adhesive as inspiration.
"We already mimic them to make fly-fishing lures," reports KQED Science. "But now scientists working on some advanced medical technology believe copycatting one tiny insect could hold promise for repairing human tissues and setting bones. Instead of stitches and screws, doctors may soon call on the next generation of medical adhesives — glues and tape — to patch us up."
Check out a video of how the caddisfly larvae pulls off this fascinating feat of design and building:
Caddisflies aren't the only species that can create adhesives that work underwater. So too can sandcastle worms, sea cucumbers and mussels. These species, which each independently evolved the ability to create an underwater adhesive, could hold clues for bioengineers looking to craft a new, helpful material for doctors and surgeons.