Meeting Abstract

47.1  Monday, Jan. 5  Hormonal regulation of sexual dimorphisms in Lichtenfelderi’s gecko (Goniurosaurus lichtenfelderi): expanding the comparative story of eublepharid lizards GOLINSKI, A.*; KUBICKA, L.; KRATOCHVIL, L.; JOHN-ALDER, H.; Rutgers Univ., New Brunswick; Charles Univ., Prague ; Charles Univ., Prague ; Rutgers Univ., New Brunswick golinski@aesop.rutgers.edu

Eyelid geckos (Eublepharidae) have a well-defined phylogeny and exhibit sexual dimorphisms in head and body size, combativeness, and pre-cloacal pore structure, yet these traits have become evolutionary dissociated. Thus, this family provides a model to study proximate mechanisms and evolution of sexual dimorphisms. A number of processes may cause phenotypic differences between the sexes. However, the correlated expression of sex-specific morphological and behavioral traits suggests coordination by a common hormonal mechanism. Previous work on other lizards has shown that these traits are testosterone (T) dependent. Here, we report studies on G. lichtenfelderi, which has genetic sex determination in common with Coleonyx elegans but mates seasonally in common with Eublepharis macularius. Our experiments included 3 groups of males (intact control, surgically castrated, castrated with T replacement) and 2 groups of females (intact control, T supplemented). Testosterone stimulated aggressive behavior and the activity of precloacal pores in males. Male sexual behavior was not affected by castration or T replacement, but T treatment induced male-typical courtship in females. Growth rate and head width were not affected by treatment in these adult lizards over a 10-week period, but the size of hemipenes was increased in males and even in T-treated females. Our experiments demonstrate that regulation of sexual dimorphisms in several morphological and behavioral traits is conserved in eyelid geckos, yet reveal some interesting differences among species. Supported by Czech Science Foundation No. 206/06/P282 (LK) and CESRI Program (AG).