INSTITUTO DE DIVERSIDAD Y ECOLOGIA ANIMAL
Unidad Ejecutora - UE
Sexual selection and dynamics of jaw muscle in Tupinambis lizards
NARETTO, SERGIO; BLENGINI CECILIA S; CARDOZO, GABRIELA; CHIARAVIGLIO MARGARITA
Lugar: Berlin; Año: 2014 vol. 41 p. 192 - 192
Abstract Sexual dimorphism patterns provide an opportunity to increase our understanding of trait evolution. Because selective forces may vary throughout the reproductive period, measuring dimorphism seasonally may be an interesting approach. An increased male head size may be important in intersexual and intrasexual interactions. In Tupinambis lizards, a big head is attributed in part to a large adductor muscle mass. Competition for mating can differ in species with different sex ratio and different degrees of sexual size dimorphism. We examined sexual differences in mass of the pterygoideus muscle, its temporal variation throughout the reproductive period and the relationship between muscle and reproductive condition in Tupinambis merianae and T. rufescens. We characterized sexual size dimorphism and sex ratio in both species. Mature males had larger jaw muscles than mature females in both species, mainly during the reproductive season. The dimorphism in jaw muscle was due to an increase in muscle mass in sexually active males. Seasonal increases in muscle mass and variation between immature and mature individuals suggest that the jaw muscle might be a secondary sexual character. We propose that the pterygoideus muscle may act as a signal of reproductive condition of males.