Cockroaches Have Personalities, Too

Feel guilty the next time you crush a cockroach

Stephen Dalton/Minden Pictures/Corbis

Let’s face it—the humble cockroach is known more as disease vector or vermin than for its winning personality. But new research might make you a bit guiltier when you squish or poison one of the infamous insects. That’s because scientists now think they have individual character traits.

To a group of researchers from the Université libre de Bruxelles, cockroaches aren’t a nuisance. They’re “gregarious insects” that can teach us about how groups approach collective decision-making. When Isaac Planas-Sitjà and his team set out to study group behavior, they were intrigued by the American cockroach because of its potential. Since cockroaches don’t have leaders, there are no followers, either—and that means that an individual insect’s personality can shine through in a group setting.

The team put RFID chips on the backs of 304 cockroaches, then divided them into groups and watched what happened when they put them in a brightly-lit, arena-like setting with a few dark shelters. Since cockroaches hate light, they predictably scuttled off to find shelter. But some roaches didn’t scurry as quickly as others. The team observed bold roaches who took their time finding cover as well as shy ones who bolted as soon as they were placed in the new environment.

“There is a collective dynamic—a social influence—that dilutes the individual personality differences,” Planas-Sitjà told Science. “So in the group, you end up with a similar behavior in everyone.” But that doesn’t negate the individual differences observed by his team. In fact, diverse personality traits can be a boon to species’ survival. That’s because more personalities lead to more behaviors, and more chances to adapt and survive.

Does the existence of shy and brave roaches mean that roaches have deeper personality traits, too? Science isn’t there yet, but recent news that wasps can recognize each other’s faces suggests that bugs may have richer lives than we give them credit for. If the prospect of personality-having, face-recognizing insects gives you the creeps, take a deep breath and remember—every intrepid cockroach is just trying to help its insect brethren live another day.

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