ACHIEVEMENT OF THERMAL-STABILITY BY VARYING METABOLIC HEAT-PRODUCTIONIN FLYING HONEYBEES

Thermoregulation of the thorax allows endothermic insects to achieve p ower outputs during flight that are among the highest in the animal ki ngdom. Flying endothermic insects, including the honeybee Apis mellife ra, are believed to thermoregulate almost exclusively by varying heat loss. Here it is shown that a rise in air temperature from 20 degrees to 40 degrees C causes large decreases in metabolic heat production an d wing-beat frequency in honeybees during hovering, agitated, or loade d flight. Thus, variation in heat production may be the primary mechan ism for achieving thermal stability in flying honeybees, and this mech anism may occur commonly in endothermic insects.