Reproductive patterns in the Baluchistan gerbil, Gerbillus nanus (Rodentia: Muridae), from western Saudi Arabia: The role of rainfall and temperature

Abstract

There is little information pertaining to the reproductive biology of the Baluchistan gerbil (Gerbillus nanus) despite a broad distribution throughout the Middle East. In the current study, body mass, reproductive-tract morphometrics plus gonadal histology and endocrine profiles of males and females were studied over 12 consecutive months in a field population of Baluchistan gerbils from the western region of Saudi Arabia in an attempt to gain insights into a) the environmental zeitgeber(s)that correlate with reproduction as well as b) to assess if reproduction is seasonal or aseasonal in this species. With the exception of testosterone all male reproductive indicators varied seasonally and were lower during winter than the rest of the year and most increased with rainfall. In contrast, ovarian mass and volume as well as immature follicle counts showed no seasonal patterns and were independent of rainfall or temperature. First pregnancies were obsereved in late spring coinciding with the increased progesterone concentrations and peaked in summer. This was accompanied by seasonal peaks in the number of Graafian follicles and corpora lutea in females and these parameters were significantly correlated with temperature, but not rainfall In the Arabian Peninsula male, but not female Baluchistan gerbils show seasonal recrudescence and this appears to be correlated largely to rainfall.

Seasonal reproduction in the Arabian spiny mouse, Acomys dimidiatus (Rodentia: Muridae) from Saudi Arabia: The role of rainfall and temperature

“…The reproductive pattern observed for A. dimidiatus in the current study strongly contrasts with those of the sympatric Baluchistan gerbil (Gerbillus nanus) during the same study period (Sarli et al, 2015). While most male reproductive parameters measured in G.…”

“…Indeed this cue has been implicated for a number of species inhabiting arid habitats (Khammar and Brudieux, 1987;Bennett, 2010, 2012a;Sarli et al, 2015). Rainfall may be used as an indicator for primary production in arid environment and affect both the quantity and quality of food (Louw and Seely, 1982;Nelson and Desjardins, 1987).…”

“…To date, little research has been reported on the patterns of reproduction in rodents from Saudi Arabia (Al-Khalili and Delany, 1986;Henry and Dubost, 2012;Sarli et al, 2015).…”

Characterizing the reproductive transcriptomic correlates of acute dehydration in males in the desert-adapted rodent,Peromyscus eremicus

“…The integral role of water as a reproductive cue for desert-rodents has also been demonstrated in water-supplementation studies (reviewed in [45,50]) as well as research on the effects of desert rainfall [51][52][53][54]. Thus, Schwimmer and Haim [46] asserted that reproductive timing is the most evolutionarily important adaptation for desert rodents.…”

“…Furthermore, watersupplementation studies among wild desert rodents resulted in prolonged breeding seasons in the hairyfooted gerbil and the four-striped grass mouse, but not in the Cape short-eared gerbil [50]. Recent research has confirmed the importance of rainfall as a reproductive cue in the Arabian spiny mouse [51], the Baluchistan gerbil [52], Chessman's gerbil [53] and the Spinifex hopping mouse [54]. The focus of this previous research was to investigate reproductive cues and consequences of water-limitation in desert rodents, namely how species have adapted breeding onset and cessation patterns to respond to water availability.…”