Diversifying selection and color-biased dispersal in the asp viper

Abstract

BackgroundThe presence of intraspecific color polymorphism can have multiple impacts on the ecology of a species; as a consequence, particular color morphs may be strongly selected for in a given habitat type. For example, the asp viper (Vipera aspis) shows a high level of color polymorphism. A blotched morph (cryptic) is common throughout its range (central and western Europe), while a melanistic morph is frequently found in montane populations, presumably for thermoregulatory reasons. Besides, rare atypical uniformly colored individuals are known here and there. Nevertheless, we found in a restricted treeless area of the French Alps, a population containing a high proportion (>50%) of such specimens.The aim of the study is to bring insight into the presence and function of this color morph by (i) studying the genetic structure of these populations using nine microsatellite markers, and testing for (ii) a potential local diversifying selection and (iii) differences in dispersal capacity between blotched and non-blotched vipers.ResultsOur genetic analyses support the occurrence of local diversifying selection for the non-blotched phenotype. In addition, we found significant color-biased dispersal, blotched individuals dispersing more than atypical individuals.ConclusionWe hypothesize that, in this population, the non-blotched phenotype possess an advantage over the typical one, a phenomenon possibly due to a better background matching ability in a more open habitat. In addition, color-biased dispersal might be partly associated with the observed local diversifying selection, as it can affect the genetic structure of populations, and hence the distribution of color morphs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0367-4) contains supplementary material, which is available to authorized users.

Evaluating taxonomic inflation: towards evidence-based species delimitation in Eurasian vipers (Serpentes: Viperinae)

“…In particular, traits related to fitness frequently present variation across different environmental and ecological conditions in order to meet the species-specific needs and enhance performance and fitness (Arnold, 1983;Kingsolver and Huey, 2003). In vipers, for instance, differences in dorsal pattern colouration can be an adaptive response to temperature gradients, enhancing thermoregulation capabilities, or to predation pressures, leading to aposematic signals or increased substratecrypsis (Wüster et al, 2004;Valkonen et al, 2011;Santos et al, 2014;Dubey et al, 2015;Martínez-Freiría et al, 2017). Increasing or decreasing scale numbers within species can influence water loss along environmental gradients (Malhotra and Thorpe, 1997;Sanders, Malhotra and Thorpe, 2004) or enhance locomotion over distinct substrates (Kelley, Arnold and Gladstone, 1997).…”