Meeting Abstract
Changes in the environment drive diversification in morphology as survival is intricately related to the constraints associated with the new habitats. Islands are strong selective environments since they provide only a limited amount and diversity of resources, thus increasing the intensity of competition compared to mainland populations. Previous studies have highlighted that changes in diet are associated with changes in skull geometry and bite force in insular lizards. However, little is known about the functional consequences of skull shape differences in association with access to food resources on islands. The present study explores whether insular lizards have converged on similar morphologies in relation to diet and variation in bite force. The heads of 140 individuals across two closely related species of Podarcis lizards from 16 islands across the Adriatic were CT-scanned, 3D surfaces of both skull and mandible were extracted and compared using 3D geometric morphometrics. Maximal bite force was measured for each individual and food items were identified after stomach flushing. We tested whether changes in diet were correlated with bite force, and whether changes in bite force were associated with variation in skull shape. We predict that higher bite forces will allow the inclusion of more plant matter and/or harder prey in the diet. Moreover, we predict changes in skull shape associated with higher bite forces. The present study will provide new insights on how insular environments select for different phenotypes and whether these differences are related to diet and biting performance.
