Reproduction, aging and mortality rate in social subterranean mole voles (Ellobius talpinus Pall.)

Abstract

Eusocial subterranean rodents of the Bathyergidae family have enormous longevity. The long lifespan of these species is associated with negligible senescence, that is, an absence of the signs of age-related deterioration in physical condition. The question arises as to whether these features are unique to eusocial Bathyergids or typical of other social subterranean rodents as well. In the present study, we analysed data from observations of a social subterranean Microtinae rodent, the northern mole vole (Ellobius talpinus Pall.), which, like mole-rats, has reproductive skew. Among the individuals captured in the wild and maintained in captivity, females that reproduced lived significantly longer than non-breeding females. We did not find any changes in muscle strength with age in any of the demographic groups studied. Faecal glucocorticoid concentrations before death were significantly higher in non-breeding females than in breeding females and males. Increased adrenocortical activity may be one mechanism responsible for the decreased lifespan of non-reproducing individuals of social subterranean rodents. We conclude that the patterns of aging, although different in some respects, are generally common for social subterranean rodents of different taxonomic groups.

Commentary: Oxidative stress as a cost of reproduction: beyond the simplistic trade-off model

“…To mention a few examples, the diet composition of non-reproducing Wilson's storm petrels (Oceanites oceanicus) significantly differed from that of reproducing individuals (Quillfeldt, 2002). Glucocorticoid concentration was found to be lower (Riou et al, 2010;Selva et al, 2011;Novikov et al, 2015) or higher (Fischer et al, 1995) in reproducing than in non-reproducing individuals. Factors like diet and glucocorticoids have been shown to influence the regulation of the oxidative balance.…”

Age-related dynamics of reproductive activity and physical conditions in Cricetidae of different ecological speciation (Rodentia)

“…Respectively the mortality curves of the two last species were more "rectangular" than those of E. talpinus and A. strelzovi, in which only a small proportion of individuals had a lifespan at least twice as long as the species median. The high level of mortality among juvenile and non-reproductive individuals was described in social bathyergids (Buffenstein 2005, Dammann & Burda 2006, Dammann et al 2011) and seems to be a common life-history trait for subterranean social species (Novikov & Burda 2013, Novikov et al 2015b. Besides the species-specific survival patterns high mortality of long-lived species may be caused by their lower tolerance to keeping conditions (Novikov et al 2022).…”

“…tests. Here we did not apply the analysis of constant samples considering long-lived individuals only (Novikov et al 2015b(Novikov et al , 2022, because such an approach restricts the time interval of valid observations and may obscure real trends in age -related dynamics. Animals that were still alive when this article was finished or occasionally died (due to the aggression of conspecifics or any accidents) were included in the analysis as censored observations.…”

“…During the last decade, we realized the multi age-point approach in comparisons of life history, behavioral and physiological traits of some species of Cricetidae family. New results of this project were regularly published (Novikov et al 2015b(Novikov et al , 2017(Novikov et al , 2019(Novikov et al , 2020(Novikov et al , 2022. Since the list of the species involved in this study has been updated and the number of completed observations has steadily increased, the release of new data remains relevant.…”

Plasma oxidative stress in reproduction of two eusocial African mole-rat species, the naked mole-rat and the Damaraland mole-rat

“…An example includes brood size manipulation, where brood size was increased to infer an increased cost to reproductive effort relative to controls [25]. Furthermore, individuals can set their limits on reproductive effort, with several characteristics, such as body condition, hormonal profile, behaviour, food availability and glucocorticoid concentration, all of which can influence reproduction [23,[26][27][28][29][30], which is likely to vary between and within species.…”