Single Gene Separates Workers from Queen Bees

Scientists have revealed how one gene in honeybees separates the workers and queens. This gene controls leg and wing development, specifically allowing to workers to develop a ‘pollen basket’.

Although previous studies have identified this gene, Ultrabithorax or Ubx, this study has looked in greater detail at the gene and identified the precise mechanisms it controls.

Ubx is present in workers but not queen bees and allows the workers to develop the features needed for their role as pollen carriers. This includes creating a smooth spot on their hind legs, where their pollen baskets (used to collect and transport pollen) are found. Additionally, the gene controls development of the ‘pollen comb’: 11 neatly spaced bristles on another section of leg. Ubx also allows the pollen press to form on the workers’ legs, which helps pack pollen for transportation.

The researchers from Michigan State University and Wayne State University unravelled the gene’s mechanisms by silencing Ubx. This reduced the size of pollen combs and pollen presses and made the pollen baskets disappear altogether.

Bumblebees are the same family as honeybees and also have pollen baskets controlled by Ubx. But in less socially complex bees (without such a defined queen and workers system), the pollen baskets are less elaborate. This led Zachary Huang, one of the authors of the study, to conclude that “the evolution of pollen baskets is a major innovation among social insects and is tied directly to more-complex social behaviors.”