Halictid bees' social behavior studied

Cornell University scientists say the social behavior of many species of sweat bees evolved simultaneously during a period of global warming.

The study, the first to link social evolution to climate change, suggests the social evolution occurred much more recently than scientists thought -- 20 million to 22 million years ago -- compared with the social evolution of other insects more than 65 million years ago.

"We believe that climatic change was a critical factor in the evolution of social behavior in these bees," said Bryan Danforth, associate professor of entomology

Halictid, or sweat, bees are eusocial, he explained, which is a type of social behavior in which the animals have permanently sterile worker castes, among other traits. Eusocial animals include honey, bumble, carpenter and sweat bees, ants, termites, many wasps as well as certain kinds of shrimp and the naked mole rat.

Halictid bees are nicknamed sweat bees because they are attracted to the salts in human perspiration.

Danforth's study will appear in a forthcoming issue of the Proceedings of the Royal Society of London, Series B, Biological Sciences.

Copyright 2006 by United Press International