Abstract
BackgroundSex-determining systems may profoundly influence the ecology, behaviour and demography of animals, yet these relationships are poorly understood. Here we investigate whether species with temperature-dependent (TSD) and genetic sex determination (GSD) differ in key demographic traits, using data from 181 species representing all major phylogenetic lineages of extant reptiles.ResultsWe show that species with TSD exhibit significantly higher within-species variance in sex ratios than GSD species in three major life stages: birth or hatching, juvenility and adulthood. In contrast, sex differences in adult mortality rates do not differ between GSD and TSD species. However, TSD species exhibit significantly greater sex differences in maturation ages than GSD species.ConclusionThese results support the recent theoretical model that evolution of TSD is facilitated by sex-specific fitness benefits of developmental temperatures due to bimaturism. Our findings suggest that different sex-determination systems are associated with different demographic characteristics that may influence population viability and social evolution.
Highlights
Sex-determining systems may profoundly influence the ecology, behaviour and demography of animals, yet these relationships are poorly understood
In this study we focused on how key demographic traits differ between TSD and genetic sex determination (GSD) systems across reptiles
Because sex differences in the age of sexual maturity influence both sexual dimorphism in body size and the adult sex ratio [22], the association we found between bimaturism and sex-determination system suggests that TSD species are likely to evolve sex differences in life history, ecology and behaviour
Summary
Sex-determining systems may profoundly influence the ecology, behaviour and demography of animals, yet these relationships are poorly understood. We investigate whether species with temperature-dependent (TSD) and genetic sex determination (GSD) differ in key demographic traits, using data from 181 species representing all major phylogenetic lineages of extant reptiles. Ever since the discovery of TSD, the causes and consequences of the evolution of alternative sex-determination systems have been a central topic in evolutionary biology research [1,2,3,4]. It is increasingly recognized that each type of sex determination is linked with a distinct set of ecological, demographic and life-history characteristics. It may help evaluate theoretical models about how the evolution of sex-determination systems may be driven by ecological and life-history traits [3, 6, 14]. On the other hand, such analyses may reveal consequences
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