The seasonality of reproduction in photoperiod responsive and nonresponsive northern red-backed voles (Myodes rutilus) in Alaska

Abstract

High-latitude arvicoline rodents usually reproduce in warmer months, but winter breeding has been documented in several species, including the northern red-backed vole ( Myodes rutilus (Pallas, 1779) Wilson and Reader, 2005; formerly Clethrionomys rutilus (Pallas, 1779)). We tested whether the reproductive condition of the species is linked to changes in environmental parameters or its body condition, and we tested the frequencies at which different reproductive phenotypes are exhibited under field and laboratory conditions. Free-living voles in south-central Alaska reached peak reproductive organ masses in spring (females) and early summer (males). Between-subject comparisons showed an effect of body mass, photoperiod, percent fat, temperature, and snow depth on reproductive organ masses, depending on the sex and breeding period (p < 0.05). One instance of late-summer photoperiod nonresponsiveness was observed, but we detected no winter breeding. Captive male voles given food ad libitum and housed at room temperature exhibited strong phenotypic variation in testis mass in response to short photoperiods. The percentage of nonresponders was 28.2% and was within the known range of nonresponsiveness for lower latitude species (20%–40%). Thus, photoperiod nonresponsive morphs are conserved in at least one arctic and subarctic species at frequencies comparable to lower latitude voles despite no observance of winter breeding in the field. Voles exhibit reproductive elasticity and may breed in winter if environmental conditions enable them.

Latitude, life history and sexual size dimorphism correlate with reproductive seasonality in rodents

“…Rodent populations of several species are known to adjust the length of their birthing season to their geographical location (Lynch et al 1981, Bronson 1985, Bilenca et al 1994, Whorley & Kenagy 2007). In species with a more limited geographic range, intraspecific variation in birth seasonality might occur because rodents are known to reproduce very opportunistically with high year‐to‐year variability, depending on various factors such as weather (Liu et al 2007, Stevenson et al 2009, Andino et al 2016), food availability (Taylor & Green 1976, Cittadino et al 1994) and population density (Batzli et al 1977, Smith et al 2006).…”

Is reproduction of male eastern rock sengis (Elephantulus myurus) from southern Africa affected by photoperiod?

“…In the deer mouse (Peromyscus maniculatus), responsiveness to photoperiod increases with higher latitude (Dark et al 1983). In contrast, responsive and non-responsive morphs have been found in a population of the northern red-backed vole (Myodes rutilus) (Dark et al 1983;Stevenson et al 2009). Most sub-tropical and tropical rodents breed opportunistically and use other environmental factors besides photoperiod to time reproduction.…”

Seasonal reproduction in the female spiny mouse from South Africa

“…The reproductive biology and environmental cues, in particular the affect of photoperiod, have been investigated in a large number of small mammals, but these studies have mainly been on species from the northern hemisphere such as hamsters (Prendergast et al , 2001), a number of Peromyscus species (Trainor et al , 2006) and voles (Stevenson, van Tets & Nay, 2009). The reproductive biology and life‐history patterns of many southern African small mammals are still largely unknown and there is an increasing need for their investigation.…”