Meeting Abstract
Bumble bees are well-known heterotherms, able to regulate high body temperatures by taking advantage of heat generation from highly active thoracic muscles. Facultative shunting of heat between thorax and abdomen not only allows bumble bees to regulate their own body temperature, but also allows them to regulate temperatures of the developing brood clump, even in extreme cold. Although the benefits of incubation for brood have been actively explored, little attention has been paid to the potential reciprocal benefits for individual workers of a colonially heated brood clump with high heat storage capacity by virtue of its size and composition. We established microcolonies of adult Bombus impatiens workers and tracked temperatures of the developing brood, nest chamber, and individual workers in response to cold challenge. As expected, workers consistently incubate brood at low temperatures, with the effectiveness of brood incubation depending on number of workers and brood clump size. Workers in microcolonies that maintain high brood clump temperature are also better able to maintain body temperatures at low ambient temperatures: previous investment of heat may directly benefit the workers as they re-absorb the heat from the brood clump as temperatures fall. These findings uncover an additional thermoregulatory strategy facilitating bumble bee persistence in extreme climates.
