Green anole image from reptilesmagazine.com.
What does it take be a good sprinter? How about a marathon runner? One might think that the traits responsible for such performance traits would be the same in males and females. If you are a green anole, that just isn’t true. Annie Cespedes, working in Simon Lailvaux’s lab at the University of New Orleans, explored the multivariate predictors of seven performance traits (sprint speed, bite force, cling force, exertion, endurance, jump power, and climbing power) in male and female green anoles. Annie explained how animals in nature rely on lots of different performance traits in their daily lives, and the large difference in body size and shape between male and female anoles might mean that the two sexes use different means to be successful in life. To add to this complexity, some individuals are just better overall at ALL performance traits than others (imagine a couch potato versus a very fit athlete), and one must account for this to understand what shapes anole performance.
Multivariate statistics allowed Annie to show that males and females do indeed differ in performance, but only in clinging ability, sprint speed, bite force, and jump power. Even more interesting, the suites of morphlogical traits that explained performance ability differed substantially between the sexes. For example, small females with large leg muscles were better sprinters and jumpers than females who are smaller and are better biters and endurance runners. What is especially important about Annie’s research is her approach. When considering how animals evolve, one must do so by simultaneously looking at a multitude of traits that might impact their survival and reproduction. By knowing how morphology predicts performance, we can begin to better understand how evolution will shape that morphology when selection acts on those performance traits.