Climate Change Could Make These Male Crustaceans Attractive to Females

Climate change is making a certain type of male crustaceans "sexier" and more attractive to females of their kind.

Researchers from the University of Adelaide have discovered that warming waters and increased carbon dioxide brought about by climate change could affect mating behavior of certain marine species.

Many species find it difficult to reproduce because of climate change. However, the shrimp-like crustaceans known as Cymadusa pemptos living off the coast of southern Australia were found to have increased their population after being subjected to warmer waters and highly acidic environment.

"Climate change most usually comes with predictions of severe negative impacts on population sizes, if not extinctions," Pablo Munguia, an ecologist and evolutionary biologist at the University of Adelaide's Environment Institute and author of the study, said in a statement.

"In general, booming populations are not predicted. It got even more interesting, however, when we dug deeper and found that males were much larger in size than in previous generations under cooler waters and lower CO2, and their bigger claws were disproportionately larger still."

In the experiment, the researchers replicated the environment of the Cymadusa pemptos in large tanks under higher temperatures and carbon dioxide levels predicted for 100 years from now. They found that warmer and CO2-rich waters stimulated the growth of algae in the tank, which are eaten by the crustaceans. The male crustaceans, in turn, grew larger in body and claw size. Males that have larger claws are more attractive to female crustaceans, and because of this, more females were interested in mating.

The researchers also found that 80 percent of females got pregnant, when normally only 30 percent reproduce under normal circumstances. Also, claw size for female crustaceans did not increase. Researchers speculated that females instead used energy from algae surplus to develop fertile reproductive organs.

"We know from previous studies that males and females can put resources towards different [biological and reproductive] investments," Katherine Heldt, a PhD student at the University of Adelaide and one of the researchers in the study, said in a report by Popular Science. "We also found in this study that the females had exponentially increased egg production under a future climate, so they're optimizing that reproductive output."

The results of the study were published in the journal Scientific Reports.