YOUNG, R. L.; BADYAEV, A. V. ; University of Arizona; University of Arizona: Influence of Muscle Attachment on Morphological Integration in the Shrew Mandible

Understanding the evolution of complex trait is a fundamental question in evolutionary biology. Central to this question is the role of correlations or integration among components of a complex trait. For skeletal traits, such correlations may result from the interaction between development (i.e. ossification) and function (i.e. mechanical stimulation from muscles). Here, we examine the influence of muscle attachment in producing and maintaining patterns of integration in the adult shrew (Sorex) mandible. We characterized patterns of integration in relation to site of muscle attachment across populations and species of three Sorex species. If the sites of muscle attachment are similar across populations and species, we predict that patterns of integration will likewise be similar. Alternatively, the sites of muscle attachment differ across populations and/or species; we predict that patterns of integration will vary in the direction delineated by variation in the muscle attachment sites.