9521543 Temperature regulation is very important for many organisms, because rates of biochemical reactions vary with temperature. Careful thermoregulation is particularly important to flight performance. Flying bees have been thought to regulate temperature of their thorax, which houses their flight muscles, by varying rates of convective and evaporative heat loss. Recent studies, however, show that flying bees reduce rates of metabolic heat production as air temperature increases. Because metabolic heat is produced mainly by the activity of the flight muscles, power output for flight may also change with temperature. This research will measure flight performance, water balance, evaporative water loss and metabolic rate in freely hovering honey bees over a range of air temperatures. The data will be used to construct quantitative heat and water budgets for thermoregulation in flying bees. It will result in the first comprehensive models of thermal effects on heat balance, water balance and flight performance in insects. The research will increase understanding of environmental constraints on the distribution, abundance, and activity patterns of biologically and economically important flying insects.
