Female anoles retain responsiveness to testosterone despite the evolution of androgen-mediated sexual dimorphism

1. The evolution of sexual dimorphism presents a challenge because males and females must express two phenotypes from the same underlying genome. In vertebrates, one solution to this challenge is to link the expression of shared traits to sex steroids. However, even ‘male-biased’ steroids such as testosterone (T) circulate at biologically significant levels in females, raising the question of whether sexual dimorphism evolves not only through the coupling of trait expression to T in males, but also through the decoupling of trait expression from T in females. 2. We tested these alternatives by asking whether male and female brown anoles (Anolis sagrei) respond to exogenous T in similar fashion with respect to a suite of sexually dimorphic traits: growth, skeletal morphology, resting metabolism, fat storage, dewlap size and dewlap colour. 3. First, we established the ontogeny of sexual dimorphism in a colony raised in a laboratory common garden. Next, we treated juveniles of each sex wit...