Incubation temperature and gonadal sex affect growth and physiology in the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination.
Temperature-dependent sex determination (TSD), in which the temperature at which an egg incubates determines the sex of the individual, occurs in egg-laying reptiles of three separate orders. Previous studies have shown that the embryonic environment can have effects lasting beyond the period of sex determination. We investigated the relative roles of incubation temperature, exogenous estradiol, and gonadal sex (testis vs. ovary) in the differentiation of adult morphological and physiological traits of the leopard gecko, Eublepharis macularius. The results indicate that incubation temperature, steroid hormones, and gonads interact in the development of morphological and physiological characters with incubation temperature resulting in the greatest differences in adult phenotype. Incubation temperature did not affect reproductive success directly, but may influence offspring survival in natural situations through effects on adult female body size. Postnatal hormones seem to be more influential in the formation of adult phenotypes than prenatal hormones. These results demonstrate that TSD species can be used to investigate the effects of the physical environment on development in individuals without a predetermined genetic sex and thus provide further insight into the roles of gonadal sex and the embryonic environment in sexual differentiation.
Tousignant
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Department of Zoology, University of Texas, Austin 78712, USA.
Crews
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D000818:Animals; D005260:Female; D006066:Gonads / Q000502:physiology*; D006728:Hormones / Q000097:blood; D008116:Lizards / Q000097:blood / Q000196:embryology / Q000254:growth & development*; D008297:Male; D011863:Radioimmunoassay; D012733:Sex Differentiation / Q000502:physiology*; D013256:Steroids / Q000097:blood; D013696:Temperature
D006728:Hormones; D013256:Steroids