It's not all grim in the battle against climate change. Once again, females have found a way to save the day.
Promiscuous female sea turtles could be mating with multiple male partners and saving their species from climate change, a new study has found.
As reptiles, turtles do not have sex chromosomes. Rather, their sex is determined by the temperature of their nest during incubation.
When eggs hatch from sand that had an average temperature of 29ºC (84ºF) throughout incubation, they produce a 50-50 mix of males and females. Warmer temperatures skew that ratio to produce more females.
This has long troubled scientists, sparking concerns that human-induced climate change will cause one species to produce just one sex, leading to extinction. Higher temperatures mean fewer males, as is the case for green sea turtles hatching at the northern end of the Great Barrier Reef.
The study, conducted by Florida Atlantic University, suggests reported male deaths might have been exaggerated.
Since 2013, biologists have been collecting blood samples from hundreds of turtle hatchlings in the Gulf of Mexico to identify the paternity of each. What they found was a surprise: DNA from a single male turtle would only appear in the nests of one female.
After calculating the number of breeding males from these tests, researchers found that for every sea turtle mother there are nearly three fathers.
No, there is no such thing as female Viagra for turtles… at least, that we know of.
Females can mate several times before the nesting season begins. They can then store sperm and lay multiple nests, so each nest will have its own unique set of fathers.
Previous research examined the number of males that could contribute to nests, but did not account for the fact that some females mate with multiple partners. Females mate at the beginning of the breeding season and then not again throughout the nesting season.
This time around in 2016, researchers examined nests laid by turtles that returned multiple times. The population has more breeding males than anyone realized.
One theory is that more males survive to adulthood, but stay in the ocean while the females return to nest.
The discovery helps scientists better understand how mating effects the population to identify how they might be impacted by extreme environmental effects.
Researchers reported their findings at the Society for Integrative and Comparative Biology's annual meeting. They plan to do further paternity testing on more Florida beaches with two of the six other sea turtle species.
[H/T: Science Mag]