Energy expenditure and body size are targets of natural selection across a wide geographic range, in a terrestrial invertebrate

One of the central questions in evolutionary ecology is how different functional capacities impact fitness, and how it varies across populations. For instance, do phenotypic attributes influence fitness similarly across geographic gradients? Which traits (physiological, morphological, life history) are most likely to be targets of natural selection? Do particular combinations of traits maximize fitness? In a semi-natural experiment, we analyzed introduced populations of an invasive species, the garden snail (Cornu aspersum) in Chile, which show low levels of genetic differentiation in spite of the distance. Specifically, we addressed whether the magnitude, sign and form of selection in snail populations could explain the differentiation (or its absence) among populations. A common garden/reciprocal transplant experiment was performed in three populations (La Serena, Constitución and Valdivia) that span a 1300 km latitudinal gradient and differ markedly in climate (semiarid North to humi...