Cockroaches Have Distinct Personalities

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Cockroaches can be bold explorers or cautious wallflowers. jo.sau [CC by 2.0]/Flickr

If you were to poll 100 people about their least favorite insect, the top prize for most hated would go to cockroaches. They aren't poisonous. They run and hide when they see us. It's just that these little guys gross us out.

But, maybe that's because we don't know them well enough. According to researchers at the Université libre de Bruxelles in Belgium, cockroaches aren’t mindless drones on a singular mission to eat our kitchen crumbs. Each insect has a distinct personality, just like you might find in a dog, pig or person.

Researchers placed radio tags on American cockroaches and put the groups in an enclosed dark setting to follow their movements. By observing each individual, they were able to see how quickly each found shelter, and how long they spent exploring their surroundings and searching for food.

When observing these groups for a period of one week, scientists found that some are, as they described them, "bold or explorers" while others are "shy or cautious," and that those personalities influence the group dynamic.

Isaac Planas Sitjà, a researcher from the university, said of the findings, "Shy individuals are those that spend more time sheltered and explore less the arena or the surroundings. Instead, bold individuals are those that spend most part of the time exploring the surroundings and spend less time sheltered."

Those personalities even influence how the insects find solutions to group problems. Researchers wrote in the journal Proceedings of the Royal Society B, "Moreover, these individual personalities have an impact both on the group personality and sheltering dynamics. Some groups quickly reach a consensus and make a collective decision, while other groups with conflicting personalities take longer to make a collective decision."

These personality traits could have something to do with the success of the species. The bolder cockroaches would be more likely to go out in search of food, a tactic that could get them killed by predators. The more cautious cockroaches, if unwilling to go out in search of food when crumbs are scarce, might not flourish either due to a lack of sufficient sustenance. Having two types of personalities helps to ensure that at least part of the population survives. As we all know, cockroaches are definitely survivors.

Sitjà added that his team is now looking into what this new information might teach us about behavior. "We are looking for behavioral syndromes that will help to categorize them and give more information about the existing synergies between personality and social behavior."

Now, will knowing that a shy cockroach is inhabiting a city-dweller's home make that person want to share a meal? Probably not. But, knowing that cockroaches are a little more like us than we imagined might just make people find a tiny bit of admiration for one of nature's hardiest species. And hopefully a little less quick to go and grab a shoe.