Reproductive strategies of bats in Africa



The reproduction of 37 species of bats from Malawi was investigated, and the strategies (litter size and chronology) of seven species were determined. Reproduction was then related to rainfall and (if possible) abundance of food. Strategies of Malawian bats were compared with strategies of bats from six other African environments with different patterns of rainfall and availability of food. Monotocous species are numerous and found in all environments, but there are few polytocous species and polytocy has not been recorded in some environments. Ten reproductive chronologies (distinguished by the timing of parturition in relation to season, the presence of reproductive synchrony, the number of pregnancies/year, and the presence or absence of postpartum oestrus) were recognized in African bats. The number and kind of chronologies occurring in different environments is variable. Four chronologies have been recorded in fruit-bats; intraspecific variability is rare, possibly because fluctuations in the abundance of fruit are comparatively small in the environments where most species of fruit-bats are found. Reproductive inflexibility may explain why most fruit-bats do not exploit diverse environments. Eight chronologies have been recorded in insect-eating bats. These bats show more interspecific and intraspecific variability than fruit-bats, probably because seasonal differences in the availability of insects are great enough to impose considerable selective pressure on reproduction. Species capable of reproductive flexibility exploit diverse environments.