The Ecology of Rattus lutreolus II*. Reproductive Tactics

Abstract

Litter size and total number of placental scars were obtained by autopsy of specimens of Rattus lutreolus from south-eastern Australia. Mean litter size in Victoria was 5 - 0, whereas on Hogan I. it was 3 -9. Although mean litter size within Victoria did not appear to vary between populations, mean number of litters per reproductive female varied between habitats. It was 1 - 5 for riparian, 2 -4 for heathland, and 3 -7 for commensal populations. The proportion of young of the year breeding also increase in this order. With the aid of information from the mark-recapture studies, it is deduced that the usual number of litters per breeding female per full breeding season is one for riparian, two for heathland, two for Hogan I., and for or five for commensal populations. Demography of populations in these habitats is discussed and possible selective pressures moulding the reproductive parameters are identified.