Abstract
In arid regions, unpredictable rainfall patterns and extreme temperature variation occurs; this poses severe constraints on reproduction in small mammals. In the present study, the gonad morphometrics, gonadal histology and endocrine profiles of the female Lesser Egyptian jerboas (Jaculus jaculus) were studied over one year in a wild population from central Saudi Arabia. An unusual rainfall pattern occurred during this study period, with three out of four seasons receiving rainfall. Pregnant females were observed during every season when rainfall fell. Yet, a distinct reproduction pattern was also observed in the reproductive parameters of J. jaculus, likely entrained by ambient temperature and photoperiodic changes, with indicators of reproductive activity being at its highest during the winter months. Jaculus jaculus, appear to possess an endogenous circannual rhythm (seasonality) of breeding, entrained by ambient temperature and photoperiod. However, they have a plasticity to their breeding strategy, which allows them to breed opportunistically. As global warming takes effect, many species which currently inhabit temperate regions may experience desertification. Understanding how species that inhabit deserts today are adapted to these harsh conditions may allow researchers to identify temperate species that are more at risk to climatic changes due to global warming.
•Female Lesser Egyptian jerboas are opportunistic breeders.•Offspring production is linked to the onset of rainfall.•Yet, female Lesser Egyptian jerboas show some seasonality in their reproduction.•Other powerful zeitgebers of reproduction in the female Lesser Egyptian jerboas are ambient temperature and photoperiod.•Jerboas combined opportunistic and seasonal breeding strategycould allow for survival in future climatic scenarios.