Meeting Abstract
Adaptation to novel habitat often involves changes in both morphology and behavior, which can interact to influence performance. Deer mice (Peromyscus maniculatus) in forested habitats have repeatedly evolved longer tails and feet than those from neighboring non-forested habitat. Previous work showed that the presence of the tail is likely critical for balance in deer mice. However, the functional significance of natural variation in tail length has not been tested, and covariance among morphological traits in wild populations makes it challenging to quantify the functional significance of each aspect of morphology independently. In addition, behavioral differences between forest and non-forest populations may interact with morphological variation to produce performance differences among populations. Here we show that forest mice from eastern and western North America have not only evolved convergent tail and foot morphologies, including increases in both the length and number of caudal vertebrae, but also exhibit convergent behavioral traits in a standard climbing assay. Even in laboratory-born, naïve mice, we observe consistent behavioral differences in both climbing preference and climbing performance between forest and non-forest populations, suggesting these differences are genetic. We then use a large, laboratory intercross between forest and prairie ecomorphs to generate mice with novel trait combinations. By quantifying climbing performance in this large recombinant population, we measure the relative importance of the various aspects of the forest morphology for climbing performance, and thus directly test the long-standing hypothesis that long tails have evolved in forest deer mice as an adaptation for arboreal locomotion.
