Insular effect on sexual size dimorphism in the clouded anole

摘要

Insular biodiversity has aroused the curiosity of biologists in assessing ecological and evolutionary hypotheses concerning their mainland counterparts. Comparisons of particular life history traits between island and mainland populations have provided a broader view of phenotypic and behavioral plasticity at both intraspecific and interspecific levels (Meiri 2007). Body size has been one of the most important biological traits used to measure phenotypic features, as it correlates with all aspects of life history and is influenced by many abiotic and biotic factors (Peters 1983). There are some studies that explore body size variation as a measure of sexual size dimorphism (Shine 1989); this measure can be male- or female-biased and is more evident in the larger species (Abouheif and Fairbairn 1997). Conversely, some investigations have shown the effects of the island rule hypothesis on body size variation, which suggests gigantism in small animals and dwarfism in large animals as a response to competition, predation, and food availability in insular environments (Van Valen 1973; Meiri et al. 2008). Lizards of the genus Anolis (Squamata: Dactyloidae) have been used as excellent models in attempting to understand ecological and physiological processes between and within species, as well as across environmental conditions (Losos 2009). Body size comparisons between island and mainland populations have been recorded in the Clouded Anole Anolis nebulosus (Hernández-Salinas et al. 2014; Senczuk et al. 2014; Siliceo-Cantero et al. 2016). These studies have shown that sexual dimorphism is higher on the island than on the mainland; however, such comparisons were conducted in a single study area per environment, and the continental and insular sites have been the same in some of the above-referenced studies. Therefore, whether similar body size patterns are different between insular and mainland populations remains somewhat unknown.