Carry-Over Effects in Nature: Effects of Canopy Cover and Individual Pond on Size, Shape, and Locomotor Performance of Metamorphosing Wood Frogs

The conditions experienced early in development can have long-term effects on an organism's phenotype and performance. We tested whether variation in canopy cover over natural wetlands affected the metamorphic size, shape, and locomotor performance of Wood Frogs (Rana sylvatica) that had developed in those wetlands as larvae. Additionally, we tested if variation in locomotor performance was mediated through larval-environment effects on frog size and shape. We captured metamorphosing frogs as they emerged from open-canopy and closed-canopy ponds, and measured locomotor performance, body length, and hindlimb length. Frogs that had developed in closed canopy ponds tended to jump greater distances than those from open-canopy ponds. The difference in jumping performance was associated with differences in body size, but not limb length. This demonstrates that canopy cover does generate carryover effects in nature. However, these effects were driven entirely by environment-induced variation in size at metamorphosis, rather than variation in relative limb-length or other variables.