Meeting Abstract

S8-1.3  Jan. 6  Evolution of sexual dimorphism in habitat use and escape behaviour in Anolis lizards. VANHOOYDONCK, Bieke*; HERREL, Anthony; IRSCHICK, Duncan J; University of Antwerp, Wilrijk; University of Antwerp, Wilrijk; University of Massachusetts, Amherst

Evolutionary biologists have long been fascinated by intersexual differences. In most cases, quantification of sexual dimorphism has remained limited to measures of intersexual differences in morphology. Yet, it currently remains largely unclear whether and how differences in morphology relate to ecological and/or behavioural differences between the sexes. In this study, we investigate the evolution of sexual dimorphism in escape behaviour among Anolis lizards and test if variation in escape behaviour is determined by variation in microhabitat use and morphology. We use Anolis lizards because they have evolved independently into a series of ecologically, behaviourally and morphologically distinct forms or ecomorphs. In addition, males and females typically differ in size, and the degree to which they do varies among species. Here, we quantify snout-vent length, microhabitat use and escape behaviour in males and females of 12 species of Anolis lizards. Our data indicate that both species and sexes show a marked difference in behavioural responses when confronted with predators. For example, whereas twig anoles have the shortest approach distance and seem to rely heavily on crypsis, grass-bush and trunk-ground anoles appear to evade predators by running. In addition, females generally have shorter approach distances and flee over smaller distances than males. Since the behavioural strategy of males seems to be determined by other morphological and ecological factors than that of females, the interspecific variation in sexual dimorphism in escape behaviour cannot be explained by interspecific differences in sexual size dimorphism or microhabitat use.