Variability of bioenergetic parameters in murid rodents of different ecological specialization

The ability to adapt to extreme environmental conditions largely depends on the mobilization capabilities of the body, which are quantified in the maximum metabolic rate that the animal is able to achieve in stressful conditions. However, the ecological patterns of the variability of the maximum metabolic rate are still very poorly studied. The paper considers 12 species of small mammals inhabiting different regions of Central Asia and belonging to various ecological groups: field and pigmy mice, Dzungarian and Daurian hamsters, flat-head, Tuvan, northern, and Korean red-backed, narrow-skulled voles, steppe lemming, northern and Zaisan mole voles, in which the values of the standard, maximum metabolic rates, metabolic rate at 15 minutes of acute cold exposure, metabolic index and ability to maintain temperature homeostasis, have been estimated by the difference in body temperature before and after the cold test. The significant impact of environmental conditions on the values of metabolic and thermoregulatory parameters, which are closely interrelated, is shown. The species of open landscapes, which are active in winter and feed on high-calorie forage, demonstrated the highest cold-resistance. The least resistant to cold stress was northern mole vole, living in a relatively thermostable underground environment. At the same time, significant variability of bioenergetic characteristics within each of the ecological and phylogenetic clade was revealed.