Abstract
The carpenter bee Xylocopa californica is active during the hot season in the southern California desert. It is endothermic during flight, with a similar to that of bumblebees and sphinx moths. Even when not flying, carpenter bees had an order of magnitude higher than typical insect resting metabolism, due to walking activity and possibly attempts to maintain high body temperature ( ). Thermal conductance was higher than in moths of similar mass. Free-flying bees kept between 39 and 46 C in air temperatures ( ) ranging from 20 to 40 C. The maximum tolerable for flight is remarkably high, about 48 C. Calculations of the standard operative temperature ( ) in paloverde trees frequented by carpenter bees indicate thatX. californica is not heat stressed until exceeds 35-38 C, and it should not experience a serious effect on foraging patterns until exceeds 41-42 C.