A low incubation temperature during the development of this lizard's egg reverses some genotypic females XX into "phenotypic" males—so that they have only functioning male reproductive organs. Keywords: Sex determinationReptilesTurtlesHormones. They conjectured that disruptive selection produced by variation in the environment could result in an evolutionary transition from ESD to GSD Bull, Vogt, and Bulmer, High levels of aromatase activity increase the production of female hormonesresulting in the development of female characteristics.
Journal of Animal Ecology.
Bibcode : GCBio. TSD may be advantageous and selected for in turtles, as embryo energy efficiency and hatchling size are optimized for each sex at single-sex incubation temperatures and are indicative of first-year survivorship. For example, there is an Australian skink lizard that is genotypically governed by X and Y sex chromosomes.
In this species, high incubation temperature during egg development reverses genotypic males ZZ into phenotypic females; so females can be ZZ or ZW, but males are always ZZ.
Zoological Science. Bibcode : Natur. Non-genetic sex determination occurs when the sex of an organism can be altered during a sensitive period of development due to external factors such as temperature, humidity, or social interactions.
Valenzuela, Nicole. Conservation Biology. Warner, Daniel, and Richard Shine. In crocodilian species—the most studied of which is the American alligator— both low and high temperatures result in females and intermediate temperatures select for males.