Is sex-reversal lending to a transition in sex-determining system in bearded dragons?
The sex of vertebrates is typically determined genetically, but reptile sex can also be determined by incubation temperature. In some reptiles, temperature interacts with chromosomal genotype to reverse sex, potentially leading to transitions from a chromosomal to a temperature-dependent sex determining system. The Central Bearded Dragon, Pogona vitticeps, exhibits female heterogamety ZZ/ZW but can have its sex reversed from ZZ male to ZZ female by high incubation temperatures. Transitions to temperature-dependent sex determination require low levels of gene flow and high more than 50% rates of sex-reversal within a population. This could be enhanced by higher fitness of sex-reversed individuals compared to concordant ZW females. Here, I compare how males, females, and sex-reversed females vary in energy use, frequency, movement, survivorship, and dispersal potential. I show that sex-reversed individuals have no difference in energy use in comparison to their female counterparts. When studying a population, the proportion of sex-reversal is moderate ~20%, and that sex-reversed and non-sex-reversed females have similar survival and movement characteristics. Across populations the rate of sex-reversal was 19%, and the species exhibits low levels of population structure FST ~ 0.001. Overall, these data do not support the proposition that a rapid transition from genetic sex determination to temperature sex determination is currently occurring in this species, but do not rule out the prospect of a more gradual transition in the future.
About Kris
My research focuses on understanding the ecology, conservation, and life-history of amphibians and reptiles. I'm especially interested in how animals interact with their environment, specifically how anthropogenic disturbances influence movements, habitat selection, energetics, and population structure of species. My goal is to integrate ecological techniques to answer physiological and evolutionary questions relating to ectotherms. When I can escape my PhD work, I enjoy piña coladas and gettin' caught in the rain.
