Invading new climates with the burden of environmental sex determination: geographic variation in sex-determining attributed in reptiles

Animals in which offspring sex is determined by cubation temperatures are faced with the challenge of producing viable sex ratios when the species' geographic distribution spans a wide thermal range. In such cases, some attribute of the mother or embryo must be adjusted, in evolutionary terms, in order to maintain sex ratios near unity. In the proposed study we will quantify geographic variations in the two maternal attributes known to influence offspring sex: timing of nesting and nest site choice. Results will elucide how these evolve to persist across wide climate ranges, and how their survival may be compromised by climate changes.