Warmer temperatures produce more female turtles, with higher egg production

June 24, 2023 by Tuhin Hosen

New research conducted at Duke University has uncovered an intriguing link between warmer temperatures, sex determination in turtles, and egg production. The study, published in the journal Current Biology on June 23, reveals that higher incubation temperatures not only result in more female hatchlings but also enhance their capacity for egg production even before their sex is determined.

The researchers discovered that higher temperatures lead to an increase in the number of “germ cells” or pre-eggs present in the embryos. These germ cells are believed to play a role in determining the embryo’s sex. Boris Tezak, the lead researcher from the Capel lab, explained that the abundance of germ cells drives the feminization process, as the temperatures conducive to female development also lead to a higher number of germ cells.

Interestingly, similar findings have been observed in fish, where increased germ cell numbers also contribute to female development. To validate the connection between germ cells and female turtles, the researchers removed some germ cells from red-eared slider turtle embryos incubated at an intermediate temperature that should have produced an equal ratio of males and females. However, they found a higher number of males than expected, further supporting the relationship between germ cells and sex determination.

Temperature-dependent sex determination has been known to scientists for many years and has been observed across various species. It appears to have evolved independently multiple times through different mechanisms. Considering the potential risks associated with relying on temperature for sex determination, particularly in the face of climate change and weather variations, the persistence of this system has remained a puzzle.

More:
https://www.thedailyscience.org/warmer-temperatures-produce-more-female-turtles-with-higher-egg-production.html