Energetics and thermal adaptation in semifossorial pine-voles Microtus lusitanicus and Microtus duodecimcostatus

Abstract

Rodents colonizing subterranean environments have developed several morphological, physiological and behaviour traits that promote the success of individuals in such demanding conditions.Resting metabolic rate, thermoregulation capacity and daily energy expenditure were analysed in two fossorial pine-vole species Microtus lusitanicus and M.duodecimcostatus inhabiting distinct areas of the Iberian Peninsula. Individuals were captured in locations with different habitat and soil features, allowing the comparison of energetic parameters with ecological characteristics, that can help explain the use of the subterranean environment and dependence of the burrow system. Results showed that M. duodecimcostatus has lower mass independent resting metabolic rate when compared with M. lusitanicus, which may be a response to environmental features of their habitat, such as dryer soils and lower water availability. Thermal conductance increased with body mass and was dependent on the ambient temperature. No significant differences were observed in the DEE, but water economy data demonstrated the influence of the water available on the habitat on the energetics of voles. These may rely on behavioural adaptations and seasonal use of burrows to cope which thermal challenges of subterranean activity and soil constraints. We found strong evidence that M.lusitanicus is able to use torpor as response to low ambient temperatures which is a new observation among Arvicolines.

Genomic resources for the North American water vole (Microtus richardsoni) and the montane vole (Microtus montanus)

“…Microtus is believed to have experienced rapid speciation and diversification, with all speciation events occurring within the past four million years [2, 3], and it has been suggested that some nominal species, such as M. pennsylvanicus , contain cryptic diversity [4]. Microtus has been an important model system across multiple biological disciplines, including studies of adaptation (e.g., [5]), infectious disease (e.g., [6]), parental care (e.g., [7]), and population dynamics (reviewed in [8]). The rapid radiation of Microtus voles has hindered systematic classification, leading to multiple taxonomic revisions and conflicting phylogenetic analyses [1, 9, 10].…”

Genetic variation at the p53 locus of two ecologically divergent Microtus pine voles: identification of molecular markers for species assignment

“…This species has bigger scapulae, a larger area for muscular insertion in the femur, and more proodont upper incisors (Mathias 1990), and its tunnels have typically less openings and more surrounding soil mounds , suggesting that possibly they are better fitted for active tunneling and inhabit deeper and less ventilated burrows than M. lusitanicus. Also, M. duodecimcostatus has a lower mass-independent resting metabolic rate (Monarca et al 2019). The distribution range of both species is also largely parapatric, with M. lusitanicus mainly found in the north-northwest part of the Iberian Peninsula and M. duodecimcostatus in the south-southeast, while cooccurring within an extended band crossing the center of the Iberian Peninsula, roughly from the Lisbon area in Portugal up to the Pyrenees.…”

“…Also, M. duodecimcostatus has a lower mass‐independent resting metabolic rate (Monarca et al . 2019). The distribution range of both species is also largely parapatric, with M. lusitanicus mainly found in the north‐northwest part of the Iberian Peninsula and M. duodecimcostatus in the south‐southeast, while co‐occurring within an extended band crossing the center of the Iberian Peninsula, roughly from the Lisbon area in Portugal up to the Pyrenees.…”

Genomic Resources for the North American Water Vole (Microtus richardsoni) and the Montane Vole (Microtus montanus)

“…It has been suggested that some nominal species, such as M. pennsylvanicus , contain cryptic diversity [ 4 ] . Microtus is an important model system across multiple biological disciplines, including studies of adaptation (e.g., [ 5 ] ), infectious disease (e.g., [ 6 ] ), parental care (e.g., [ 7 ] ), and population dynamics (reviewed in [ 8 ] ). …”