Meeting Abstract
In the Sonoran Desert, the radiant heat from highly absorbent surfaces carries the extreme heat of the day well into the night and, with climate change, nocturnal minimal temperatures have increased more than diurnal maxima. As these phenomena are expected to intensify, there is the potential to affect the available foraging time for nocturnal aerial insectivores. We examined the thermoregulatory capacity of six Sonoran Desert bats: pallid bat, Antrozous pallidus, big brown bat, Eptesicus fuscus, California myotis, Myotis californicus, western pipistrelle, Parastrellus hesperus, California leaf-nosed bat, Macrotus californicus, and Brazilian free-tailed bat, Tadadarida brasiliensis. We measured resting metabolic rates, body temperature, rates of evaporative water loss and thermal tolerance using flow-through respirometry. All species had relatively modest thermal tolerance limits (~40 ° C) compared to nocturnal birds (~48-64 ° C)and some nocturnal rodents. A limited capacity for evaporative heat loss and lthal body temperatures of ~43 ° C appear to contribute to these differences in performance in the heat.
