Predator-driven Phenotypic Variation in Mosquitofish
The rapid and dramatic changes in biotic and abiotic characteristics following tidal creek fragmentation is predicted to generate substantially different selection pressures for organisms inhabiting the system than were naturally present before anthropogenic impacts. In this NSF funded project (with Brian Langerhans, North Carolina State University) we are testing a priori predictions of phenotypic differentiation based on explicit hypotheses of divergent natural selection between fragmentation regimes. Our model organism is a small endemic, livebearing fish species, Bahamas mosquitofish (Gambusia hubbsi). The work will determine the relative influence of natural selection in driving predictable phenotypic outcomes, the role of history (genetic drift and unpredictable events) in yielding stochastic phenotypic variation, and the importance of gene flow in constraining phenotypic divergence (and the reverse causation of divergent selection constraining gene flow).