Shedding light on the role of photoperiod, rainfall and ambient temperature on the breeding physiology of male Lesser Egyptian jerboa (Jaculus jaculus) from central Saudi Arabia

Abstract

This study aimed to assess the seasonal reproductive strategy occurring in the male Lesser Egyptian jerboa (Jaculus jaculus) and determine which environmental cues are responsible for initiating reproductive recrudescence. Body mass, morphometry of the reproductive tract, the histology of the testes and the circulating testosterone concentrations in wild male J. jaculus, from central Saudi Arabia, were studied over 12 consecutive months. Furthermore, sixteen additional males were collected and subsequently placed on either a short-day (SD) or a long-day (LD) light schedule under controlled laboratory conditions. Using these male reproductive parameters, we investigated the potential proximate environmental cues that may trigger the onset of reproduction. Unexpectedly, males were reproductively active during three out of the four seasons, namely autumn, winter and spring possibly due to the rainfall that fell at an unprecedented frequency and quantity during this time. However, we revealed the importance of other environmental triggers, namely photoperiod and ambient temperature, on the control of male reproduction in J. jaculus. Decreasing photoperiod (SD) and ambient temperature were observed to activate the reproductive system by increasing plasma testosterone concentration. The male Lesser Egyptian jerboa was found to exhibit a marked seasonal reproduction controlled by the environmental cues of ambient temperature and photoperiod.