Reproductive seasonality of the bush rat (Rattus fuscipes greyi) South Australia

Abstract

The reproductive seasonality of the bush rat (Rattus fuscipes greyi) was investigated in Scott Creek Conservation Park near Adelaide, South Australia, by catch and release trapping conducted at irregular intervals over a 4-year period in a population of higher density than previously reported for this species. A seasonal pattern in breeding activity was observed with the production of young in spring and summer (October-February) with a peak in December. There was seasonal variation in the testicular index of males with minimal values from April to June. Some animals may have retained the ability to mate throughout the year but there was no evidence of offspring surviving from any winter matings. Differences were seen in the timing and intensity of the non-breeding season between years. Possible causes of reproductive seasonality were seasonal changes in vegetative growth and the abundance of fungi and insects and predictive cues provided by seasonal changes in ambient temperature and photoperiod.