When we think of silk, we usually think of silkworms. But bees make silk too.

In many bee species, it is the larvae rather than the adult bees that produce silk. They use it primarily to spin protective cocoons as they develop. Ants and wasps, close relatives of bees, also have species whose larvae produce silk.

What has caught scientists' attention is that some bee silk is built differently from silkworm silk. Silkworm silk relies heavily on protein structures called beta sheets. The silk produced by honeybee larvae and some other members of the bee, ant, and wasp group contains proteins that form coiled-coil structures, in which protein strands twist together somewhat like tiny ropes.

Researchers are studying these proteins to understand how they assemble and whether they can be produced artificially. Scientists have already experimented with making bee-silk proteins using genetically engineered microorganisms, opening the possibility of creating materials without having to collect silk from bees.

Why bother making bee silk? Its protein structure could provide a useful starting point for designing lightweight, biodegradable materials with properties tailored for particular jobs. Researchers have explored potential uses ranging from fibers and films to coatings and biomedical materials.