Variation in the timing of reproduction of the four-striped field mouse, Rhabdomys pumilio, in the Eastern Cape Province, South Africa

Abstract

We used the four-striped field mouse, Rhabdomys pumilio (Sparrmann, 1784), to  test the hypothesis that reproduction in a small, short-lived mammal will be  opportunistic, characterized by temporal and spatial variation in the timing of events, and only be inhibited under harsh and predictable winter conditions. Field mice were trapped for three years in two regions of the Eastern Cape Province of  South Africa, one that experienced a predictable and harsh winter (Mountain Zebra National Park; MZNP) and  the other which experienced a milder winter (Thomas Baines Nature Reserve; TBNR).  There was no winter inhibition of reproduction at TBNR, while at MZNP female reproductive activity was inhibited but males continued to produce spermatozoa in  winter. We interpret this flexibility in the timing of reproduction as supporting an opportunistic reproductive strategy which may be an adaptation to the seasonal and  often unpredictable climate of the region.

Key words: opportunistic reproduction; seasonal reproduction; reproductive inhibition.