In order to regulate their body temperature as efficiently as possible, wild female bats switch between two strategies depending on both the ambient temperature and their reproductive status. During pregnancy and lactation, they profit energetically from clustering when temperatures drop. Once they have finished lactating, they use torpor* to a greater extent, to slow their metabolic rate and drop their body temperature right down so that they expend as little energy as possible. These findings by Iris Pretzlaff, from the University of Hamburg in Germany, and colleagues, were just published online in Springer's journal Naturwissenschaften The Science of Nature.
When energy demands are high, such as during pregnancy and lactation, female bats need to efficiently regulate their body temperature to minimize energy expenditure. In bats, energy expenditure is influenced by environmental conditions, such as ambient temperature, as well as by social thermoregulation clustering to minimize heat and energy loss. Torpor, another common temperature regulation strategy, has disadvantages for reproductive females, such as delayed offspring development and compromised milk production.
Pretzlaff and team investigated, for the first time in the wild, the thermoregulation strategies used by communally roosting Bechstein's bats during different periods of their reproductive cycle pre-lactation, lactation, and post-lactation. They collected data from two maternity colonies roosting in deciduous forests near Wrzburg in Germany, predominantly in bat boxes. The authors measured ambient temperature over those three periods as well as the bats' metabolic rate by using respirometry (measuring the rate of oxygen consumption).
They found that the bats' metabolic rate was strongly influenced by the ambient temperature. However, by roosting in groups (social thermoregulation), the bats were able to regulate their body temperature more effectively, despi
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