Overwinter body temperature patterns in captive jerboas (Jaculus orientalis): influence of sex and group

Abstract

The jerboa (Jaculus orientalis) has been described in the past as a hibernator, but no reliable data exist on the daily and seasonal rhythmicity of body temperature (T (b)). In this study, T (b) patterns were determined in different groups of jerboas (isolated males and females, castrated males and grouped animals) maintained in captivity during autumn and winter, and submitted to natural variations of light and ambient temperature (T (a)). T (b) and T (a) variations were recorded with surgically implanted iButton temperature loggers at 30-min intervals for two consecutive years. About half (6/13) of isolated female jerboas hibernated with a T (b) < 33°C, with hibernation bouts interspersed with short periods of normothermy from November to February. Hibernation bout durations were longer (4-5 days) than those of normothermia phases (1-4 days). During hibernation, the minimum T (b) was low (T (b)min ~10.7°C). In contrast, one of the 12 isolated males showed short hibernation bouts of ca. 2 days late in the hibernation season, February-March. The males had T (b)min values of 15.1°C. In contrast to predictions, no castrated males hibernated. When jerboas were grouped, females and males exhibited concomitant torpor bouts. In males, the longest bouts were observed during the late hibernation season. These data suggest complex regulation of hibernation in jerboas.

Coordinated seasonal regulation of metabolic and reproductive hypothalamic peptides in the desert jerboa

“…Indeed, Siberian hamsters adapted to a short photoperiod display a decrease in body weight associated with an increase in Somatostatin gene expression (Herwig et al, ; Dumbell et al, ). In the present study, we observed a significant increase in Somatostatin gene expression in spring as compared to autumn, which is in line with the reported decrease in the jerboa's body weight in spring and summer (El Ouezzani et al, ). Therefore, Siberian hamster and jerboa appear to display opposite but coordinated seasonal variations in both Somatostatin gene expression and body weight.…”

“…It displays seasonal variations in the nocturnal production of melatonin (Lakhdar-Ghazal et al, 1992) and melatonin inhibits testicular activity in male jerboas (El Qandil et al, 2004). Additionally, previous studies reported that jerboas display seasonal variations in body weight and food intake (El Ouezzani et al, 2011;Talbi et al, unpublished data). The seasonal changes in reproductive activity are accompanied by variations in the content of hypothalamic peptides involved in the central control of reproductive activity.…”

“…The jerboa is a semi-desert rodent whose reproductive and metabolic activities are well adapted to marked environmental changes. This species is sexually active in spring and early summer (Ghobrial and Hodieb, 1973;El Ouezzani et al, 2000;El Qandil et al, 2004) and hibernates at low ambient temperatures (Andjus et al, 1974;El Ouezzani et al, 2011). It displays seasonal variations in the nocturnal production of melatonin (Lakhdar-Ghazal et al, 1992) and melatonin inhibits testicular activity in male jerboas (El Qandil et al, 2004).…”

Kisspeptin and RFRP-3 differentially regulate food intake and metabolic neuropeptides in the female desert jerboa

“…The differential effect of Kp on females’ food intake may be related to their different sexual and energy status between both seasons. Indeed at spring, when coming out of hibernation, female jerboas are sexually active with reduced body weight35 and express higher ARC Kp immunoreactivity18 as compared to autumn. It might be interesting to compare Kiss1r distribution and Kp neuronal connection to POMC and RFRP neurons between spring and autumn to help understand the seasonal differences in the metabolic action of Kp.…”

“…The jerboa is a particularly interesting animal model living in a semi-desert milieu characterized by large annual variations in environmental temperature, water and food supply. In autumn/winter, when the natural conditions are unfavorable, jerboas shut down their reproductive activity3233, increase their food intake and body weight and hibernate3435, while in spring/summer when favorable conditions return, the animals display opposite regulations with a reactivation of reproduction and reduction in body weight and food intake32333536.…”