Seasonal Changes in Locomotor Performance and Bite Force in a Non-Territorial Lizard

Many species in temperate climates exhibit seasonal variation in behavior, with mating and reproduction restricted to one season. Reproductive behaviors elicited by males include finding mates, establishing territory, and defending mates or territories from competing males. The ability to perform such behaviors will impact an individual’s reproductive success and in turn, its overall fitness. In non-territorial species, male home ranges often overlap and encounters between competing males are more likely. Mate guarding has evolved in many non-territorial species, where males will follow and defend a female from competing males to secure mating opportunities and paternity of offspring. In polygynous lizards, social dominance and reproductive success have been linked to the performance capacity of key behaviors used in male-male combat, such as biting and locomotion. Thus, biting and locomotor performance can directly affect the ability of a male to acquire females and defend them to ensure paternity of offspring. While the ability to perform such behaviors at high capacity during the breeding season can increase male fitness, there may be costly trade-offs associated with the maintenance of these capacities in the post-breeding season. In this study, bite force performance, locomotion performance, and morphological traits were measured in a population of male Aspidoscelis sexlineatus lizards. Data was collected from lizards (n=75+) for the duration of an activity season, from the onset of the breeding season until lizards retreated for hibernation. This study examines how these traits vary among seasons to understand seasonal variation in behavior and performance in a non-territorial lizard species. Ultimately, these data will be combined with hormonal data to quantify the mechanisms by which seasonal changes in performance occur