Photoperiodicity in daily rhythms of body temperature, food and energy intake of the golden spiny mouse (Acomys russatus)

The golden spiny mouse, Acomys russatus, exists in the most arid and warm habitats oflsrael's Rift Valley. This species is nocturnally active, but becomes diurnal when it coexists with the common spiny mouse, Acomys cahirinus. Therefore, we studied the responses of A. russatus to changes in photoperiod. Daily rhythms of body temperature (T_b), apparent digestible dry matter intake (DDMI), gross digestible energy intake (GDEI), water intake, and body mass were measured in A. russatus kept at an ambient temperature of 28 °C, and acclimated to two different photoperiod regimes: 16L:8D (long photophase; LP-mice) and SL: 16D (long scotophase; LS-mice). In LS-mice, the duration of elevated T_b was longer than in LP-mice. DDMI, GDEI, and water intake were significantly higher in LS-mice. No differences were recorded in body mass. The results of this study show that, as in other desert rodent species, thermoregulatory mechanisms of A. russatus respond to changes in photoperiod. Therefore, such changes may be used as cues for seasonal acclimatization.