Development of sexual dimorphism in two sympatric skinks with different growth rates

Sexual-size dimorphism (SSD) is widespread in animals, especially in lizards (Reptilia: Squamata) and is driven by fecundity selection, male-male competition or other adaptive hypothesis. However, these selective pressures may vary through different life history periods, thus it is essential to assess the relationship between growth and SSD. In this study, we tracked SSD dynamics between a “fading-tail colour skink” (Blue tail skink whose tail is only blue during its juvenile stage: Plestiodon elegans) and a “non-fade colour” tail skink (retains a blue tail throughout life: P. quadrilineatus) under a controlled experimental environment. We fitted growth curves of morphological traits (Body mass, SVL, and TL) using three growth models (Logistic, Gompertz and von Bertalanffy). We found that both skinks have male-biased SSD as adults. Body mass has a higher goodness-of-fit (as represented by very high R2 values) using the von Bertalanffy model than the other two models. In contrast, SVL an...