A queen bee may be shaped by more than its famous royal diet.
The wax of the peanut-shaped chamber where the queen develops has distinct physical and chemical properties that help steer its development, researchers report June 3 in Nature. By analyzing the chamber’s composition and the larvae it harbors, the team challenges the long-held notion that royal jelly alone — the queen-making food fed to select larvae — makes a queen.
“The discovery is very cool and thought-provoking,” says Thomas Seeley, a biologist at Cornell University who was not involved in the work. “To me, queen cells have long seemed important because odors from a developing queen may permeate the wax walls, marking them as very special spots that workers recognize and don’t accidentally damage.”
But for entomologist Boris Baer, the cells posed a question born of years observing his own colonies. “Bees spend so much time and energy constructing these cells that it made little evolutionary sense if they were merely larger food containers,” says Baer, of the University of California, Riverside. “Could the cell itself contribute to queen development?”
Baer and colleagues studied western honeybees (Apis mellifera) and eastern honeybees (Apis cerana), comparing queen- and worker-cell wax, the workers that build the cells and how larvae fare in each wax environment.
The first clues came from the wax. Analyses showed that queen-cell wax is softer, less dense and chemically distinct from worker-cell wax.
The next finding came as a surprise, Baer says. The “royal nurses” building “royal cribs” for their future queens “spend longer [than worker cell builders] constructing these cells, run hotter than other bees and show distinct patterns of gene [activity],” suggesting they are specially adapted to modify the wax they work with.
But the strongest evidence came when the team let queen-destined larvae develop on royal jelly for four days, then replaced the caps on their artificial queen cells with wax from either queen or worker cells. Up to about two-thirds of larvae under worker-cell wax died, compared with roughly a third under queen-cell wax. They also developed into smaller pupae, while queens reared under queen-cell wax more closely resembled those left undisturbed in their natural cells.
“Everything was supporting the same conclusion,” Baer says. Bees do more than feed the queen — they “actively engineer them.”
Exactly how that engineering works remains unclear. Kai Wang, an apiologist at the Chinese Academy of Agricultural Sciences in Beijing, says the distinct chemical scents he and the team found inside the cells are especially intriguing. “Are they influencing the developing queen’s senses, preparing her for mating and life after emergence?” he wonders. “Are some produced by the larva herself? And could the future queen be actively communicating with the workers constructing her chamber?”
The researchers plan to trace when during development the wax environment exerts its effects. But the implications extend beyond queen development, Baer says. “These superorganisms mobilize specialized workers that collectively shape the next generation,” he says. “The division of labor in bees might be much more complex than we have acknowledged so far.”
