Female Frogs Make Offspring Grow Faster Amidst Global Warming

Some female frogs are making their offspring grow faster in the midst of global warming, new research shows, adjusting the rate depending on the date of reproduction.

As the climate changes, plants and animals are seeing a notable acceleration of the date when reproduction and other life processes occur. In order to compensate, over recent decades many organisms have adjusted accordingly, including Rana arvalis, an amphibian species located in northern Europe.

Female frogs of this species have the ability to influence both the growth rate and the development of their offspring, and given the changes global warming is causing, they are utilizing this skill to their advantage.

According to researcher Germán Orizaola, "the mechanism by which the female frogs can condition the growth of their larvae could be due to the genes associated with the maintenance of their biological clock being transferred to the embryos and becoming active even before fertilization."

"This would provide the larvae with the exact information regarding the progression of the growing season," he added in a statement.

A changing climate means that environmental conditions can vary and be unpredictable, so animals don't often know when the best time to reproduce is. Normally, Rana arvalis, commonly known as the moor frog, reproduce from March to June, AmphibiaWeb reports. But now to ensure their offspring's survival, the females speed up reproduction and development rates.

To test this adaptation in the lab, researchers delayed the date of reproduction, which simulated a time of environmental instability. The result was an equivalent reduction in the growth period for the larvae.

"That means the later this species of frog breeds, the faster the larvae develop," explained Orizaola, the study's co-author.

The findings are described further in the journal Ecology.

Moor frogs are one of the most abundant species in Central and Eastern Europe, as well as West Siberia. When they reproduce, females will lay anywhere from 500 to 3,000 eggs, all of which she tries to protect from the environmental elements.