Bumblebee specialization studied

SEATTLE, Jan. 23 (UPI) -- U.S. scientists have determined how bumblebee colonies maintain fairly stable nest temperatures - and they do it by specializing.

By exposing bumblebee nests to a range of temperatures, the University of Washington and the University of Puget Sound researchers found worker bees buffer their nest from temperature extremes. Some workers specialized in raising the temperature in a nest when they incubated the colony's young developing bees or brood. Other workers fanned their wings to cool the nest when conditions became too warm.

The scientists also found the performance of various in-nest tasks is not interchangeable among the social insects. Instead, they found strong evidence for job specialization, said Sean O'Donnell, a UW associate professor of psychology and member of the research team.

"We expected that larger workers would be incubators, but we found to our surprise the opposite was true," O'Donnell said. "We don't know whether the smaller bees are really better at warming the nest, or whether the larger bees avoid incubating for other reasons."

The researchers studied Bombus huntii, a bumblebee species common in the Pacific Northwest.