While an individual’s sex is determined by sex chromosomes in mammals and birds, there is a diversity of sex-determination systems in ectotherm vertebrates. In these latter taxa, besides sex chromosomes, certain environmental conditions, especially temperatures experienced during early ontogeny can influence the sexual development of the individuals.

These sex-determination systems are not mutually exclusive, and thus, high or low temperatures may override the sex encoded by the individual’s sex chromosomes, resulting in sex reversal.

Although research data generated mainly in laboratory experiments for decades have suggested that environment-induced sex reversal could be widespread across ectotherm vertebrates, there is a huge knowledge gap regarding its molecular background, physiological and ecological consequences, frequency in wild populations as well as its importance in the evolution of these taxa.

Because of the ongoing climate change, it is urgent that we learn how changing environmental temperatures can affect the global biodiversity.

Therefore, we collected species-specific data from the literature on genetic and temperature-dependent sex determination, temperature-induced sex reversal as well as sex-reversal frequency in wild populations across amphibians and reptiles. We named this database HerpSexDet, the herpetological database of sex determination and sex reversal, and published it in 2023. We plan to release regular updates of this database in the future.

About the curators of HerpSexDet

We are researchers mainly focusing on evolutionary ecology, molecular ecology and behavioural ecology. Although we both started our research careers in different fields, now our main focus lays on consequences of anthropogenic environmental changes in ectotherms.

Edina Nemesházi is a post-doc researcher at the Konrad Lorenz Institute of Ethology, Department of Interdisciplinary Life Sciences, University of Veterinary Medicine Vienna (Austria). https://enemeshazi.hu/en/

Veronika Bókony is a senior researcher at the Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Budapest (Hungary). http://evolecol.hu/people/veronika-bokony

Randomly changing header images:

  • Rana dalmatina eggs. Photo: Nikolett Ujhegyi
  • Bufo bufo tadpoles. Photo: Nikolett Ujhegyi
  • Coloured copies of a photo of an adult Rana dalmatina. Photo and design: Edina Nemesházi