Reproductive photo-responsiveness in male forest shrews (Myosorex varius) from the Eastern Cape of South Africa

A number of environmental factors regulate the reproductive physiology of an organism. Life history traits, such as length of gestation and ovulation patterns of individual species, may result in reproduction being either seasonal or aseasonal. Seasonal breeding can be regulated by the relative amounts of daylight and darkness to which a mammal is exposed. This in turn limits the time during which conception can occur. Consequently, induced ovulation is often found in species with short life spans since it ensures conception after copulation. Reproductive responses to a change in photoperiod were investigated for the short lived, forest shrew (Myosorex varius). After male shrews were exposed to either a long or a short photoperiod for 6 weeks, testicular histology revealed that reproduction appears to be photoresponsive under a long photoperiod, implying that reproduction could be seasonal. Scanning electron microscopy images of the penis revealed the presence of epidermal spines which implies that Myosorex varius may exhibit induced ovulation.