Meeting Abstract
P3.23 Jan. 6 Phenotypic and Genetic Variability in a Latitudinal Gradient in Populations of the Garden Land Snail, Helix aspersa, in Chile. ARTACHO, P.*; SILVA, A; POULIN, E; NESPOLO, RF; Univ. Austral de Chile, Valdivia, Chile; Univ. Austral de Chile, Valdivia, Chile; Univ. de Chile, Santiago, Chile; Univ. Austral de Chile, Valdivia, Chile paulinaartacho@uach.cl
The study of intraspecific phenotypic variability is relevant for the understanding of how differences in evolutionarily important traits, such as life histories and physiological traits can evolve and are affected by ecological and geographical factors. Moreover, in broadly distributed species, intraspecific clinal patterns of variation have been frequently attributed to the action of natural selection, which may favor genetic differentiation and the local adaptation of populations to particular environmental conditions. With the aim of analyzing the adaptive latitudinal variability in energy utilization and organismic performance, we measured standard metabolic rate (SMR), mean speed (MS) and maximum dislodgment force (MDF) in 300 individuals of Helix aspersa along a ca. 1600 km latitudinal gradient across Central-South Chile (three equidistant populations). Individuals were acclimated during one month (20�C, 14 : 10 light: dark) before measurements. In addition, we studied the population genetic structure of these populations through five microsatelital loci. Results showed that significant differences in SMR (ml CO2 h-1), MS (cm/m) and MDF existed between populations of H. aspersa, with greater values of these traits towards high latitudes. Moreover, this land snail exhibited significant neutral genetic differentiation between populations. Differences in SMR, MS and MDF, which are presumed to influence fitness, between populations of H. aspersa may indicate that they have diverged in response to local selective pressure (e.g., temperature, predators). In addition, the neutral genetic differentiation may suggest that this species showed limited gene flow, favoring the maintenance of these phenotypic differences.
