Fine spatial scale phenotypic divergence in wood frogs (Lithobates sylvaticus)

I studied local divergence in growth, a trait previously shown to be both phenotypically plastic and heritable, among wood frog (Lithobates sylvaticus (LeConte, 1825)) tadpoles inhabiting four ponds within a continuous woodland. Mark-recapture results revealed very low levels of migration among ponds as close as 35 m and no more than 185 m apart. Common garden experiments conducted at two temperatures revealed consistent year-to-year patterns of phenotypic divergence in tadpole growth performance among the four pond populations. The divergence in growth performance was conserved when controlling for parental effects via half-sibling experiments. Results of cross-transplant experiments suggest that the divergence in tadpole growth reflected either genetic drift or adaptation to local pond conditions. Taken together, the results suggest that divergence in growth performance among the tadpoles from the four ponds is the result of selection or genetic drift reinforced by low levels of gene flow among pond populations.