Meeting Abstract
Understanding pre-copulatory sexual selection in a wild population is often hindered by our ability to document copulations in real time. While studies often demonstrate that large males sire more offspring, higher mating success is inferred indirectly or often assumed, with few empirical tests demonstrating the same. In this study, we used fluorescent powders to assess mating rates for different size classes of males in a wild population of the sexually-dimorphic brown anole, Anolis sagrei . We captured nearly all males from a closed island population and powdered them around the cloacal region with one of four unique fluorescent colors, corresponding to non-overlapping size classes. We then, released these males on the island and captured adult females after a span of two days. We noted the presence as well as color of any powder on the cloaca and dorsum of the females, indicating copulation with males of that size class. We found that copulation rates were twice as high late in the breeding season (July, 52.86%) compared to earlier in the season (May, 25.54%). Overall, 2% of females were found to have mated multiple times, as inferred from multiple colors on the same individual. Across seasons, large males had significantly higher number of copulations (57.6%) compared to small males (42.3%). Additionally, females that mated were significantly larger than those that did not. Our study provides direct evidence for pre-copulatory sexual selection on larger body size in males. Future studies will focus on assessing if large males also sire more offspring.
