Make haste slowly: reproduction in the Zaisan mole vole (Ellobiustancrei)

Abstract

Mole voles are the most specialized subterranean members of the subfamily Arvicolinae. We assess the basic reproductive parameters of the Zaisan mole vole (Ellobius tancrei Blasius, 1884) and compare our data with the characteristics reported for other Ellobius species and surface-dwelling voles. In most respects, reproduction of the E. tancrei follows the pattern that is typical for voles. Females undergo postpartum estrus, but rarely combine pregnancy with lactation. The rate of embryonic and postembryonic growth (0.13 and 0.54 g/day, respectively) are slightly lower, whereas the relative neonate and weanling masses (8% and 40% of maternal mass, respectively) are slightly higher than the respective values predicted for non-subterranean arvicolines. The combination of these trends results in the protracted pregnancy and lactation (both ∼30 days). The age at first breeding is delayed (>2.5 months). Despite heavy weanlings, total maternal investment per litter in E. tancrei is low due to small litter size (2.31). Although the species of Ellobius are similar to each other by the parameters of developmental time, they vary by litter size, total investment per litter, and possibly by relative neonate body mass. This is consistent with the idea that when body-size effect is removed, fecundity variables and degree of precociality at birth are dissociated from timing variables.

Rapid development of mature vocal patterns of ultrasonic calls in a fast-growing rodent, the yellow steppe lemming (Eolagurus luteus)

“…Our data regarding the rapid physical growth (1 g body weight gain per day from birth to 40 d of age) are consistent with earlier data reporting the similarly fast postnatal body weight gain in captive pup yellow steppe lemmings originated from the same natural population [78]. Among 39 investigated Arvicolinae species, the absolute body weight gain is faster (1.14 g per day) only in the European water vole Arvicola amphibious [90][91][92].…”

Dental radiography as a low-invasive field technique to estimate age in small rodents, with the mole voles (Ellobius) as an example

“…Subterranean lifestyle, cooperative breeding and unusual life history traits (Letitskaya 1984, Evdokimov 2001, Moshkin et al 2007; Kaya and Coşkun 2015, Smorkatcheva et al 2016; Smorkatcheva and Kuprina 2018) make mole voles excellent experimental models for population and behavioral ecology. The age structure of E. talpinus populations is complex due to extremely long (by arvicoline standards) lifespan which is up to six years even in free-ranging animals (Evdokimov 2001).…”