Reproductive potential of a vole pest (Arvicola scherman) in Spanish apple orchards

Abstract

Fossorial water voles, Arvicola scherman, feed on tree roots causing important damages in European apple orchards. Since the intensity of crop damage produced by rodents ultimately depends on their inherent capacity to increase their population, the main goal of this study was to determine the reproductive potential of the subspecies A. scherman cantabriae in apple orchards from Asturias (NW Spain), where voles breed over the whole year. Our results were compared with those reported for the subspecies A. scherman monticola from the Spanish Pyrenees (where reproduction ceases in winter). Sexual characteristics, body condition, relative age class and number of embryos were recorded from 422 females caught in apple orchards along two years. We found pregnant females all along the year, which were able to produce a high number of litters per year (7.30) although litter size was relatively moderate (first year: 3.87 embryos/female; second year: 3.63 embryos/females). The potential number of pups per female and year (first year: 28.25; second year: 26.50) was substantially higher than that reported for Pyrenean voles, what is probably related with differences in the length of the breeding season and in life histories between subspecies. In our population, the number of implanted embryos correlated positively with the body condition of the mother. Our results reveal that management efforts should not be seasonal as they used to be so far and invite to explore the physiological consequences of management practices.

Divergence time estimation using ddRAD data and an isolation-with-migration model applied to water vole populations of Arvicola

“…Samples of different localities of A. scherman and A. amphibius were obtained through a combination of our own collections from previous studies 30 , 31 , loans from museums, and skull bones sampled from barn owl pellets (Supplementary Table S1 ).…”

“…Arvicola scherman is a fossorial species that inhabits lowland and upland grasslands across the main mountainous region of south-western and central Europe 22 , 29 . Because of their relatively-high population growth and frequent multiannual fluctuations of density, this species is considered a harmful agricultural pest in many areas 30 , 31 . In the Iberian Peninsula, A. scherman has two geographically isolated populations recognized as subspecies, different from the subspecies of central Europe 32 .…”

First reported case of albinism in Montane water vole

“…Notwithstanding, coat coloration may vary between populations. No case of albinism was reported from other studies based on wide samples of specimens from the Pyrenees (Ventura 1988) and the Cantabrian mountains (Somoano 2017).…”

“…aitors@serida.org and the Cantabrian mountain range (Ventura 2007), where they may reach high population densities because of relatively-high reproductive potential (Ventura & Gosálbez 1990, Somoano et al 2016. It is in Lugo province where an albino specimen of this species was captured on 25 th December 2018 in a meadow intended for mowing (UTM 29T 649619 4733990; 1,205.7 m.a.s.l.)…”

A Bocage Landscape Restricts the Gene Flow of Pest Vole Populations

“…Nonetheless, a loss of genetic variability in these fossorial water voles due to increased variance in reproductive fitness [ 90 ] seems unlikely. Mild temperatures, even in winter, and ample food all the year around allow populations to continuously breed and to show a high reproductive potential in this geographic area [ 36 , 91 ]. Because a population outbreak occurred during fieldwork in the whole sampling area, genetic differentiation caused by low dispersal rates during a demographic crash could be also rejected [ 38 ].…”