Patterns of reproduction in two sympatric gerbil species in arid Egypt

Abstract

Despite a significant number of studies on the reproductive characteristics of small mammals, very little of this work has been conducted on species in Egpyt. Here, the Egyptian greater gerbil (Gerbillus pyramidum Saint-Hilaire, 1825) and Anderson's lesser Egyptian gerbil (Gerbillus andersoni De Winton, 1902) in northeastern Egypt were surveyed. Breeding behavior in these species was synchronized with rainfall in the winter and spring months. Surprisingly however, the removal of individual gerbils throughout the course of study resulted in an extension of reproductive activity into the dry summer and autumn months in the latter part of the sampling. These results are discussed in the context of density-dependent reproductive behavior in small mammals.

Breeding periods of Gerbillus cheesmani (Rodentia, Muridae) in Saudi Arabia

“…This corresponds to what has been observed in many semi-arid or desert countries for gerbils and other small rodents (Happold 1966, Prakash 1971, Amirat et al 1977, Withers 1983, Sicard and Fuminier 1994, Tripathi 2005, Krug 2007, Soliman and Mohallal 2009, Shenbrot et al 2010 ). In G. cheesmani , the reproduction of most individuals coincided with the local rainfall during the study period, but not with the average pluviosity of the country.…”

“…Gerbillus cheesmani was clearly a seasonal breeder in Saudi Arabia, like Gerbillus dasyurus in the Negev (Shenbrot et al 1997 ) and several species in N. Sudan (Happold 1966 ) and in W. Algerian Sahara (Amirat et al 1977 ), but unlike other desert regions where rodents may reproduce more or less throughout the whole year, e.g., in the Negev (Sinai et al 2003 ), the Sinai (Soliman and Mohallal 2009 ), the Namib (Krug 2007 ), the Tahr (Tripathi 2005 ), and in Chile (Lima et al 2003 ). The capture of most young G. cheesmani 2 months after the peak in pregnant females confirmed the seasonal character of reproduction in this Saudi Arabian species.…”

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

“…Food availability is significant for breeding animals since reproduction is costly and the synchronization of breeding with rainfall and food availability has been confirmed in a number of rodent species (Neal, 1984;Predavec, 1994;Soliman and Mohallal, 2009 (Happold 1966, Amirat et al, 1977. In contrast,rodents from other desert regions for example the Namib, Sinai, Egypt, the Negev and the Tahrbreed throughout most of the year (Reichen, 1973, Sinai et al, 2003, Tripathi 2005, Krug, 2007, Soliman and Mohallal, 2009). These differences between our findings and those of the studies highlighted above may be explained by differences in the climate at these localities; for example in our study rainfall is sporadic and unpredictable.…”

“…The most important factors influencing reproduction in this small rodent appears to be rainfall in males and temperature in females.While males undergo reproductive recrudescence females maintain their reproductive function throughout the year, possible due to different gonadal response times between the sexes. As with the Egyptian greater gerbil and Anderson's lesser Egyptian gerbil breeding is synchronized with rainfall (Soliman and Mohallal, 2009). However, unlike…”

“…Recrudescence of reproduction with the onset of rainfall has been found to arise in many species of rodents in desert regions of the world for example, Arvicanthis niloticus in the Sudan (Happold, 1966), Gerbillus gerbillus and Psammomys obesus in the Sahara (Amiratet et al, 1977),Gerbillus dayurus in the Negev (Shenbrotet al, 1977) and Gerbillus pyramidium and Gerbillus anersoni in Egypt (Soliman and Mohallal, 2009). Dietary salinity of food may act as an important cue to the body to stop reproduction when salinity is high or to initiate the direction of energy towards reproduction when they are low, as has been found in golden spiny mice (Acomys russatus) in the deserts of the Middle East and deer mice (Peromyscus maniculatus) from North America Desjardins 1987, Wube, 2009).…”