Thermoregulatory differences in African mole-rat species from disparate habitats: Responses and limitations. (February 2020)

• Record Type: Journal Article
• Authors: McGowan, Natasha E.; Scantlebury, David M.; Bennett, Nigel C.; Maule, Aaron G.; Marks, Nikki J.
• Is Part Of: Journal of thermal biology. Volume 88(2019)
• Publication Date: 2020-02
• Subjects: Mole-rat -- Temperature -- Thermoregulation -- Habitat -- Climate change -- Adaptation; Ta Ambient temperature -- Tb Core body temperature -- Ts Body surface temperature -- VO2 Oxygen consumption -- LME Linear mixed effects -- AIC Akaike's Information Criterion -- LCT Lower Critical Temperature -- UCT Upper Critical Temperature -- RMR Resting Metabolic Rate; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2019.102495
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: Individuals and populations possess physiological adaptations to survive local environmental conditions. To occur in different regions where ambient temperature varies, animals must adopt appropriate thermoregulatory mechanisms. Failure to adjust to environmental challenges may result in species distributional range shifts or decreased viability. African mole-rats (Bathyergidae) occupy various habitats in sub-Saharan Africa from deserts to montane regions to mesic coastal areas. We examined thermoregulatory characteristics of three African mole-rat species originating from disparate (montane, savannah, and arid/semi-arid) habitats. Animals were exposed to various ambient temperatures, whilst core body temperature and the surface temperature of different body parts were measured. Oxygen consumption was determined as a measure of heat production. Core body temperatures of Natal (montane) mole-rats ( Cryptomys hottentotus natalensis ) increased significantly at ambient temperatures >24.5 °C, while those of the highveld ( Cryptomys hottentotus pretoriae ) (savannah) and Damaraland ( Fukomys damarensis ) (arid/semi-arid) mole-rats remained within narrower ranges. In terms of surface temperature variation, while pedal surfaces were important in regulating heat loss in Natal and Damaraland mole-rats at high ambient temperatures, the ventral surface was important for heat dissipation in Damaraland and highveld mole-rats. This study provides evidence of the variation and limitations of thermo-physiological mechanisms for three mole-rat species relative to their habitats. Information on physiological adaptations to particular habitats may inform predictive modelling of species movements, declines, and extinctions in response to a changing environment, such as climate change. Highlights: Thermo-physiological responses of mole-rat species from different habitats varied. Cold-adapted species tended to overheat at high ambient temperatures. Warm-adapted species were able to lose more heat from their ventral surfaces. Heat loss from the feet may be important at temperatures above thermoneutrality.