Thermal regime drives a latitudinal gradient in morphology and life history in a livebearing fish

Within-species diversity is often driven by changing selective regimes along environmental gradients. Here, we provide a direct test of the environmental factors underlying phenotypic diversity across the wide native distribution of eastern mosquitofish (Gambusia holbrooki). We investigated life-history and body-shape divergence (including multiple measures of body size) across more than 14 degrees of latitude in North America, and used Akaike’s...