Flight activity of Noack's round-leaf bat (Hipposideros cf. ruber) at two caves in central Ghana, West Africa

摘要

Noack's round-leaf bat Hipposideros cf. ruber is widely distributed in sub-Saharan Africa. Here, we present some aspects of its ecology from two caves in central Ghana. Our main objective was to assess the nightly and annual flight activity and to examine the influencesof ambient temperature on flight activity. We tested the hypothesis that flight activity of the species is concentrated at certain periods of the night and the year using mist-netting data from 2,712 captured bats. We found no evidence for annual fluctuations in flight activity, probably dueto no distinct seasonal limitation of food resources, no migration, and the lack of extreme environmental conditions in the study area. Our hypothesis of concentrated nightly flight activity was confirmed for one cave but not for the other. Flight activity was concentrated early in the night(20:00, 21:00 and 22:00 hours) at one cave, possibly to take advantage of locally available early active prey insects, while it was uniformly distributed throughout the night at the other. Lastly, we found a reduction in the flight activity of H. cf. ruber when there was a distinctdrop in temperature over the night. We therefore suggest the reduction in flight activity may result from the direct effects of temperature on prey abundance as the bats responded by reducing activity to avoid excessive prey search costs.