Reproduction of Angola free-tailed bats (Tadarida condylura) and little free-tailed bats (Tadarida pumila) in Malawi (Central Africa) and elsewhere in Africa

Abstract

Angola free-tailed bats and little free-tailed bats occur in diverse habitats throughout most of Africa south of the Sahara. This study investigated the reproductive strategies and related biology of these species in Malawi where they were sympatric, and analysed data from elsewhere in Africa to show how the strategies varied along a gradient of habitats from approximately 12°N to 25°S. Both the Angola free-tailed bat and the little free-tailed bat were normally monotocous. Angola free-tailed bats invariably had 2 births/year, and the interval between consecutive births decreased with increasing latitude. When the interval was shortest (~90 days) a post-partum oestrus occurred. Little free-tailed bats differed by having a shorter gestation (~60 days), and the ability to have up to 5 births/year with a post-partum oestrus after each birth. The extent to which this potential is achieved varies with latitude and rainfall, mainly so that lactation can coincide with peaks in the abundance of food. The interaction between rainfall and reproductive characteristics results in the two species having patterns of reproduction which are sometimes similar, but more often different. Competition between the species is unlikely to be affected by differences in their reproduction.