Biology and Molecular Structure of the α-Fibrous Silks in Bees, Ants, Wasps and Hornets (Hymenoptera).

Larval aculeate insects (bees, ants and hornets) have evolved a silk for cocoon and nest construction based on entirely different design principles from the convergently evolved silk of spiders and silkworms. The silk is based on the coiled coil protein structure: a structure proposed in the 1950s by Francis Crick, where multiple α-helical proteins wrap around each other to form a supercoil. Whilst now recognised as a ubiquitous protein assembly motif, the purity of silk pulled from the honeybee silk gland made it one of the earliest experimentally validated examples of this structure. Here, we describe the current state of understanding of the relationship between the coiled coil structure and aculeate silk biology gained from early studies dating from the mid-twentieth century up to the present time. Further, efforts to replicate the natural material and functional materials generated from the silk are outlined. Finally, we consider the future of research in this area, focusing on mimicking natural silk and the use of recombinant silk for rational design of functional materials.