A temperature shift of just one or two degrees Celsius determines whether American alligator eggs hatch as male or female, infobae.com reported.
Researchers at the University of Georgia published these findings in the Journal of Experimental Biology, detailing experiments conducted on 146 eggs collected from seven nests in South Carolina. The study reveals that the thermal threshold for producing female hatchlings begins at 33.9 degrees Celsius, which is lower than previously understood, according to Phys.org reporting cited by infobae.com.
Previous laboratory experiments used constant temperatures that failed to reflect the natural thermal swings of wild nests. To overcome this limitation, the research team led by doctoral student Karin Ebey and associate professor Benjamin Parrott incubated eggs at five different temperature averages ranging from 30 to 33.9 degrees Celsius, incorporating daily fluctuations of approximately 2.8 degrees Celsius.
The resulting mathematical model connects these fluctuating incubation conditions directly to biological sex determination. Cooler temperatures near 30 degrees Celsius and higher temperatures reaching 36.1 degrees Celsius or more produce primarily females. Meanwhile, intermediate values between 32.2 and 33.3 degrees Celsius skew the population toward males.
Short heat periods reaching up to 35.6 degrees Celsius do not harm alligator embryos, contrary to earlier hypotheses. Instead, these brief warm spells increase the likelihood that the embryos develop as females.
We know, thanks to the monitoring of the nests, that these temperature cycles fluctuate,
Benjamin Parrott said, according to infobae.com. But we also know that a small difference can cause mostly males or females to be born.
Parrott emphasized the broader implications for reptile populations under climate change. This is very relevant to understanding how the environment is going to change in the near future,
he stated, as reported by infobae.com. If temperatures are affecting the sex ratio, that is a serious problem.
American alligators act as ecosystem engineers by modifying habitats in ways that benefit other species. The new mathematical model provides conservationists with a precise instrument to predict hatchling sex based on nest temperatures.
This work is important because it ensures we have an accurate tool to be able to say:
Karin Ebey explained, according to infobae.com.
Researchers intend to expand this predictive method to other reptiles with temperature-dependent sex determination, including sea turtles, crocodiles, and freshwater turtles. Parrott noted that despite this progress, researchers must still conduct more studies to accurately forecast sex ratios across multiple reptile species.