Effect of Dietary and Predatory Conditions on Wood Frog (Lithobates sylvaticus) Morphology

Elaine Langone Center, Terrace Room

Diet is a critical factor in the growth and development of organisms. Additionally, chemical cues from predators have the potential to induce phenotypic plasticity in morphology and development of the prey species. In its larval stages, the wood frog (Lithobates sylvaticus) is known to feed on plant matter as well as dead animal tissues and the eggs of other amphibians found within the same vernal ponds. The benefits of consuming a meat or plant based diet over one another are unclear in L. sylvaticus. We hypothesized that tadpoles would express anti-predatory morphological responses at a greater degree when fed both plant and meat based foods. To test the hypothesis, 60 L. sylvaticus tadpoles were raised under six conditions: three dietary conditions (meat, vegetation and a combination of both foods) crossed with two predatory conditions (presence or absence of chemical cues from predatory dragonfly nymphs (Family Aeshnidae)). Over a five week period, tadpoles were fed ad libitum. At the end of the feeding period, we recorded developmental staging, gut length and 12 morphological measurements of each tadpole. Furthermore, we ran a y-maze experiment at weeks two and four in order to test for preference between a meat or plant based diet. Although y-maze data was inconclusive, the results also showed significant effects of diets on the morphological measurements while effects of the predatory cues and the interaction between the two factors were not significant. This data potentially hints at possible benefits of a combination diet over solely meat or plant based feeding in regards to growth and development.