Quantifying the age- and sex-dependent morphological variation in two syntopic mustelids: Martes martes and Martes foina

Abstract

a b s t r a c tAge determination is a prerequisite to establish reliable age and sex-specific patterns of morphological variation between individuals, populations and species. In this paper, we explored sex and age morphological variations in pine and stone martens in the same region of Bresse (France) during the same period. Using a large dataset of stone martens and pine martens genetically identified, we discriminated individuals using a set of morphological measurements (body mass, head-and-body length, tooth wear, tail length, neck circumference, posterior foot length, baculum length) and evaluated their power in correctly classifying individuals in three age classes: juveniles, subadults and adults. We then derived cross-sectional growth curves for the two species and estimated the age at the end of growth by adjusting sex and species-specific von Bertalanffy growth curves. Our results showed that sub-adults and adults are difficult to disentangle based on morphological measurements, especially because subadults reached adult size by the age of eight months. On the adults, the sexual size dimorphism in favor of males for all traits we measured was clearly more pronounced in pine martens than in stone martens. Stone martens showed significantly larger measurements than pine martens of the same sex, except for head-and-body length which was not significant and posterior foot length which was larger in pine martens. We discussed our results in the light of various hypotheses concerning biogeographical variation and long-term morphological divergence. Our results suggest that inter-specific differences in morphology might facilitate coexistence of both species in the same area.

Using pedigree relations to inform capture‐recapture data for the estimation of census population size

“…The stone marten is a medium‐sized (body mass = 1–2 kg, body length = 40–55 cm; Ruette et al 2015 a ) solitary carnivore with principally nocturnal activity (Kalpers 1984, Herr et al 2010). Stone martens occur at low densities, ranging from 0.7 to 5.8 individuals/km 2 (Lachat Feller 1993, Herr et al 2009) and they show an intra‐sexual territoriality with the male's home range (76–376.3 ha) overlapping those of several females (4.3–163 ha; Powell 1979, Mergey et al 2011, Larroque et al 2018) and with a polygynous mating system where males monopolize several females.…”

“…In Bresse, France, the stone marten can be legally trapped and hunted, as it is considered a pest species (Larroque et al 2016 b ). This population has been studied in depth for different aspects of its ecology, and previous studies mostly require the age determination of the individuals through the analysis of teeth cementum annuli (Ruette et al 2015 a , Larroque et al 2016 b ). We therefore have a multi‐year hunting bag of known‐age individuals that were all genotyped at 17 microsatellite loci (Larroque et al 2016 b ) supplemented by roadkill recoveries with the same information.…”

Morphological variation and allometry of the baculum in stoats, Mustela erminea (Carnivora, Mustelidae) from Western Carpathians

“…Morphology of the mustelid baculum has been described in several studies (Burt 1960, van Soest & van Bree 1970, King & Moody 1982, Grue & King 1984, Barysh nikov & Abramov 1997, Abramov & Baryshnikov 2000, Baryshnikov et al 2003, Elsasser & Parker 2008, Ruette et al 2015, Čanády & Onderková 2016a, which show that this bone tends to be rather simple in structure but with some more complex projections at the tip. A multi-male mating system occurs in many species of Mustelidae (Lariviére & Jennings 2009), so the baculum may be under strong sexual selection.…”