HERREL, A.*; VANHOOYDONCK, B.; IRSCHICK, D.J.; University of Antwerp, Belgium; University of Antwerp, Belgium; Tulane University, New Orleans: Ontogeny of head shape, bite performance and diet in the Jamaican lizard Anolis lineatopus

As different life-history stages of a species potentially compete for the same prey, natural selection can be expected to give rise to intraspecific differences in morphology and performance that reduce intraspecific competition. Here we test whether different lifehistory stages and sexes differ in their head shape and size, bite forces and diet to test for reduced competition through niche divergence. Our results show that bigger lizards eat bigger and harder prey. Juveniles bite disproportionately hard for their size allowing them to eat relatively large prey. Moreover, males, females and juveniles differ significantly in their head size and shape as well as in the size and hardness of prey eaten. Multiple regression models indicate that head shape and size-corrected bite force are significantly correlated to prey size. Moreover, for a given prey size males tend to eat harder prey than females and juveniles. These data suggest that natural selection has shaped the ontogeny of head shape resulting in differential bite performance in juveniles, males and females of Anolis lineatopus. This allows animals of different sex and size classes to consume different prey, thus reducing intraspecific competition.