Down in the Wadi: The locomotory activity rhythm of the Arabian spiny mouse, Acomys dimidiatus from the Arabian Peninsula

Abstract

The circadian rhythm of locomotory activity in the Arabian spiny mouse, a desert living species, was investigated under controlled laboratory conditions. Ten individuals were subjected to successive light cycles. When subjected to a 12L:12D light cycle, locomotor activity was confined mainly to the dark phase (mean 94.2% ±1.6%). During a period of constant darkness (DD), all animals expressed free running rhythms of locomotor activity (mean 23h49 ± 0h04). Following a second LD cycle, the light and dark phases were inversed (12D:12L). Activity shifted with the lights and was masked during the light phase, reentrainment was rather slow (up to 10 days). The effect of varying ambient temperature (20 to 35 o C) on the locomotor activity under a 12L:12D cycle revealed that temperature had no distinct effect on the level of locomotor activity. When the dark component of the day was lengthened to 8L:16D, the mean percentage of activity during the dark increased to 96.0 ± 0.8 %, while a significant decrease in night time activity was observed when the dark phase length was decreased to 16L:8D (78.29 ± 2.52%). The Arabian spiny mouse therefore behaves as other desert dwelling rodents and can be described as truly nocturnal.

The comparative gastrointestinal morphology of five species of muroid rodents found in Saudi Arabia

“…A. cahirinus was found to be mainly nocturnal (Nowak and Paradiso, 1983) and reduced urine production in this species enables it to be very resilient in extreme dry conditions (Harrison and Bates, 1991). A. dimidiatus exhibited nocturnal activity under laboratory conditions (Alagaili et al, 2013).…”

Diversity and Conservation of Rodents in Saudi Arabia

“…Studies on the locomotory activity rhythm for Eliomys melanurus, Acomys dimidiatus, Meriones rex, Meriones lybicus and Gerbillus dasyurus were investigated [18][19][20][21]. Rodents remains in owl pellets were studied by several authors, providing additional locality records [22][23][24][25].…”