This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The independent evolution of the same traits in different organisms is strongly indicative of adaptation. However, similarities can also exist because of common genetic, developmental, scaling, and functional constraints and could only rarely arise because of similar genetic changes to a shared environmental challenge. Traits might also come to resemble each other because of plastic, or non-genetic change, in response to the same environmental stimuli. This proposal will test the relative importance of jaw plasticity for the convergent evolution of molluskivory, eating hard-shelled snails and clams, in cichlid fishes. Plasticity in the cichlid jaw that results from bone growth in response to the mechanical stress of crushing could contribute to the success of these fishes. If jaw remodeling results in more similar phenotypes than expected by chance, this would implicate plasticity as key to cichlid trophic adaptation. The outlined approach integrates phylogenetic reconstruction, experimental lab studies of phenotypic plasticity, finite element analysis, and the generation of null models of phenotypic evolution to test how phenotypic plasticity contributes to structural convergence in the cichlid jaw. In this series of studies, we will determine: 1) How has trophic specialization on mollusks evolved during the Heroine cichlid diversification? 2) Is plasticity more important than non-plastic divergence in adapting the jaw to crushing forces? and 3) Does force-induced plasticity increase morphological convergence in the cichlid jaw? This work will support several undergraduate and graduate students and contribute to our understanding of how the mechanical strength of bone changes during evolution. Increasing our understanding of how bone remodels during evolution could ultimately shed light on degenerative bone conditions such as osteoporosis.
