Bees: what gives them their ability to collect pollen?
It turns out that a single gene is largely responsible, scientists believe. The gene, known as Ultrabithorax, or Ubx, is responsible for leg and wing development in insects. In honey bees, it plays a crucial role in the formation of pollen-carrying structures.
“This gene is critical in making the hind legs of workers distinct so they have the physical features necessary to collect pollen,” said Zachary Huang, an entomologist at Michigan State University. “Other studies have shed some light on this gene’s role in this realm, but our team examined in great detail how the modifications take place.”
The team, which included researchers from Wayne State University, found that Ubx inhibits the development of bristles on the hind legs of worker bees, causing them to develop a smooth, bristle-free spot that hosts their pollen baskets.
On another part of the bees’ legs, the gene promotes the formation of 11 neatly spaced bristles called the pollen comb, and the pollen press, a protrusion that packs gathered pollen into tight pellets.
Although the gene exists in both workers and queens, only workers develop these specialised features. The scientists note that Ubx expression appears to be controlled by environmental factors such as diet – which explains why queens, who are fed a rich diet of royal jelly in their larval stage, don’t express Ubx the way workers do.
When the scientists isolated and turned off Ubx in worker bees, their legs looked more like those of a queen – the pollen baskets disappeared, and the growth of pollen combs and presses was inhibited.
Huang hopes his research could lead to ways to improve bees’ pollination abilities, crucial at a time when bee colonies are collapsing. While it won’t solve that problem, it could make remaining bees more efficient.
Bill Condie is a science journalist based in Adelaide, Australia.
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