Impending death alters crickets’ standards for mates

With a short time to live, parasite-infested females lose their preference for fast-chirping males

With parasitic flies gorging on her guts and the end approaching, a variable field cricket may have only one thing to do: Find a mate.

UNWANTED WINGMAN A parasitic fly sits next to a variable field cricket. To increase their chances of reproducing, fly-infested females may seek out and mate with less-desirable male crickets. Courtesy of Oliver Beckers

Usually, female Gryllus lineaticeps prefer males with fast chirps. But when being eaten alive by fly larvae, female crickets don’t wait around for a snappy tune. Instead, they settle for slow-chirping sexual partners, evolutionary biologists Oliver Beckers of Indiana University in Bloomington and William Wagner Jr. of the University of Nebraska-Lincoln report in the April Animal Behaviour.

Parasitic flies seek out crickets as potential homes (and meal tickets) for their young. Before the fly larvae chew through crickets’ bellies, female crickets have about a week to find a mate and lay eggs before dying.

To find out whether infestation lowered females’ mating standards, Beckers and Wagner placed fly larvae on female crickets and then played slow and fast chirp recordings from loudspeakers set in separate corners of a square chamber. Healthy females walked toward the fast chirping sound about 80 percent of the time, while infested females split their devotion about equally.

“They don’t invest a lot of time and energy finding the super sexy guy,” says Beckers. “They’ll go for the average Joe.”

Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.

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