Good pollen makes bees hot, biologists at UC San Diego have found. Wasps warm up too when they find protein-rich meat, a separate experiment has shown.
In both cases warmer flight muscles likely speed the insects' trips home, allowing them to quickly exploit a valuable resource before competitors arrive, the researchers report in separate studies, published this month in two scientific journals.
Because foragers of neither species eat the protein they collect, feeding it instead to their larvae, their warming must be a behavioral rather than a metabolic response to nutritious food, both research teams conclude.
Such similar responses found in two distantly related species a bumble bee and a yellowjacket wasp whose ancestral lines diverged millions of years ago suggest that the behavior is an ancestral trait. Bumble bees, but not yellowjackets, recruit fellow foragers to help gather good food; and they are still extra warm when they return to the hive.
"This is information that other bees could potentially use," said associate professor of biology James Nieh who leads the research group that published both papers. Their elevated body heat could be a signal to other bees that has acquired a meaning beyond its original physiological function.
Western yellowjackets (Vespula pensylvanica) invaded Hawaii on a shipment of Christmas trees in the late 1970s. "Wasps forage on any kind of meat they can find: animal carcasses, other insects," said UCSD doctoral student Megan Eckles. Their appetite for protein and efficient foraging are harming Hawaiian spider and insect populations.
Eckles and biology graduate student Erin Wilson traveled to Hawaii to see if behavioral heating increased the wasps' predatory prowess. "The warmer a wasp's body is, the faster it can fly," Eckles said, and the more efficiently it can harvest its prey.
Eckles found four colonies of these was
|Contact: Susan Brown|
University of California - San Diego