Abstract: While foraging from the dense inflorescences of spiraea (Spiraea latifolia) and goldenrods (Solidago sp.), both workers and drones often allowed thoracic temperature (TsubTh) to fall below the minimum for flight. The bees were physiologically capable of maintaining a high TsubTh, but the periodic decrease in TsubTh was strongly correlated with ambient temperature (Tsuba). Decreases of TsubTh were unrelated to fuel reserves carried in the honey stomach. Drones foraging from the inflorescences were more likely to have low TsubTh than workers, even though on the average they carried several times greater fuel reserves in their honey stomach. Within workers, old or parasitized (by conopid flies) individuals were more likely to forage with low TsubTh than young an unparasitized individuals. Workers, unlike drones, showed an increasing tendency to decrease TsubTh with decreasing body mass. Although the decrease in TsubTh while foraging ('torpor'), with its associated sluggishness, appears to function as an energy-conservation mechanism, it could also be a risk-averting mechanism. By maintaining a high TsubTh and flight readiness, workers can 'gamble' on the chance of finding a new food source, unlike drones who do not have the hive's energy resources to fall back on if they deplete their supply of stored fuel.