The most important insect leg of mankind

The most important insect leg of humans, the pollen basket (corbicula) of bumblebees, honeybees, stingless bees and orchid bees

For thousands of years, bees have played an important economic and cultural role in human societies, as Egyptian hieroglyphs and Mayan codices attest. Their importance as pollinators for ecosystems and plant production, and thus for food security, is increasingly recognised. The most important are probably the corpuscular bees, i.e. honeybees, bumblebees, orchid bees and stingless bees. These bees possess the evolutionary novelty of the pollen basket (corbicula) on their hind legs - a widened, flattened/concave, polished/shelfless outer surface of the hind tibia that is lined with long hairs. The corbicula is only present in females, i.e. it is sexually plastic and serves to collect/transport large clumps of pollen. Despite its conspicuousness, the EvoDevo bases of the corbicula are almost completely unexplored. A study in honeybees has shown that the Hox gene ubx facilitates the suppression of corbicula development in never-seeking queens by shifting the identity of the legs. Deciphering the developmental regulation will help to understand the evolutionary origin and adaptations of the corbicula in bees - the key morphostructure that makes them so successful and important for human food security.

In this project, we will investigate the evolution of this iconic trait and the basis of its sexual plasticity. Thanks to funding from EASIGENOMICS (Horizon 2020), we have the opportunity to apply Spatial Transcriptomics (10X Visium) in combination with ATACseq and RNAseq as a functional genomics foundation for subsequent comparative genomics (evolution of corbicula in bees).