Rainforest Flies May be Able to Withstand Climate Change

Scientists believe some species, like the Drosophila birchii  rainforest fly, may be able to evolve and adapt to the effects of climate change, new research suggests.

However, their survival is dependent on the condition that environmental changes aren't too abrupt or dramatically altered beyond the conditions that a species currently experiences.

Previous research offered a bleak prospect for tropical species' adaptation to climate change, now researchers from Monash University are hopeful that certain species can avoid extinction.

"Whilst many believe some species have the evolutionary potential to adapt no one really knows for sure, and there are fears that some could become extinct," lead author Dr. Belinda Van Heerwaarden said in a statement.

Building off of an experiment from 2000, Van Heerwaarden, Dr. Carla M. Sgrò, from the Faculty of Science and colleagues tested the ability of tropical flies native to Australian rain forests, Drosophila birchii, to withstand potential future conditions as a result of climate change.

In the prior study, researchers exposed these flies to very dry conditions - a drastic change compared to the damp tropical rainforest. Most flies died within hours, and those that did survive and were left to breed over 50 generations were no more resistant to climate change's effects.

This time around, Van Heerwaarden and Sgrò changed the conditions from 10 percent to 35 percent humidity to see if that would make a difference, considering 10 percent humidity is extreme and likely not representative of future conditions.

"In our test we decreased the humidity to 35 percent, which is much more relevant to predictions of how dry the environment will become in the next 30 to 50 years. We discovered that when you change the environment, you get a totally different answer," Van Heerwaarden said.

While on average most of the flies did not survive past 12 hours, some did. By comparing different families of flies, the researchers discovered the difference in the flies' resistance is influenced by their genes.

After allowing the longest-living flies to breed over five generations, they found that one species evolved to survive 23 percent longer in 35 percent humidity.

"Tropical species make up the vast majority of the world's biodiversity and climactic models predict these will be most vulnerable to climate change. However these models do not consider the extent to which evolutionary response may buffer the negative impacts of climate change," Sgrò explained.

"Our research indicates that the genes that help flies temporarily survive extreme dryness are not the same as those that help them resist more moderate conditions. The second set of genes are the ones that enable these flies to adapt."

The research was published in the journal Proceedings of the Royal Society B: Biological Sciences.