Locomotor activity and body temperature rhythms in the Mahali mole-rat (C. h. mahali): The effect of light and ambient temperature variations. (January 2019)

• Record Type: Journal Article
• Authors: van Jaarsveld, Barry; Bennett, Nigel C.; Hart, Daniel W.; Oosthuizen, Maria K.
• Is Part Of: Journal of thermal biology. Volume 79(2019)
• Page Start: 24
• Page End: 32
• Publication Date: 2019-01
• Subjects: Tb core body temperature -- Tc constant ambient temperature -- Tn natural ambient temperature -- LDs square wave 12L:12D -- LDn natural wave 12L:12D -- DD constant darkness; Body temperature -- C. h. mahali -- Circadian rhythms -- Locomotor activity -- Mahali mole-rat; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2018.11.013
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: African mole-rats (family: Bathyergidae) are strictly subterranean mammals that reside in extensive networks of underground tunnels. They are rarely, if ever, exposed to light and experience muted temperature ranges. Despite these constant conditions, the presence of a functional circadian clock capable of entraining to external light cues has been reported for a number of species. In this study, we examine a social mole-rat species, Cryptomys hottentotus mahali, to determine if it possesses a functional circadian clock that is capable of perceiving light and ambient temperature cycles, and can integrate these cues into circadian rhythms of locomotor activity and core body temperature. Eight male and eight female, non-reproductive individuals were subjected to six cycles of varying light and temperature regimes. The majority of the individuals displayed daily rhythms of locomotor activity and body temperature that are synchronised to the external light and temperature cycles. Furthermore, endogenous rhythms of both locomotor activity and core body temperature were displayed under constant conditions. Thus, we can conclude that C. h. mahali possesses a functional circadian clock that can integrate external light and temperature cues into circadian rhythms of locomotor activity and core-body temperature. Highlights: Mahali mole-rats display endogenous rhythms of locomotor activity and body temperature. Mahali mole-rats can use both light and ambient temperature to entrain their locomotor activity rhythms. This is the first study to use ambient temperatures ramps simulate natural temperature cycles. There are indications that ambient temperature may be a prominent zeitgeber for circadian rhythms in this mole-rat.