Different personalities are thought to help the survival of the species because it increases the chances of at least some surviving when disaster strikes

This article is more than 5 years old

This article is more than 5 years old

Cockroaches may be ugly, they may be among the most loathed creatures on the planet but at least, scientists say, they have personality.

Researchers studying the behaviour of the insects have discovered that far from simply being a homogenous mass they have individual character traits.

The discovery is unlikely to change perceptions of them from skittering vermin to desirable beasts but it could go some way to explaining their evolutionary success.

Scientists observed the character traits as they studied the way the “gregarious insect” seeks shelter when they come out into the open.

If they had the same personalities they would all behave exactly the same when in the open but observations have revealed clear differences.

Some, those classified as shy, keep hidden as much as possible and seek the safety of shelter while the more adventurous are keen to explore their surroundings.

Isaac Planas Sitjà, one of the researchers from the Université libre de Bruxelles which uncovered the personalities, said: “We have categorised the observed personalities. We call them “shy or cautious” and “bold or explorers”.

“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.”

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In a statement summarising their findings, published in the journal Proceedings of the Royal Society B, the research team said: “From studying the way they find shelter, we show that individuals have consistent behaviour which can differ between individuals in a group - cockroaches have personalities.”

Different personalities are thought to help the survival of the species because by driving different behaviour it increases the chances of at least some surviving when disaster strikes. The personalities of individuals can also, the team found, affect the behaviour of groups of cockroaches.

Cockroaches used in the tests were measured for the speed with which they found shelter and the time they spent exploring and seeking out new supplies of food. In their natural environment the differences in personality could improve the chances of adventurous cockroaches finding extra food but simultaneously increase their chances of being preyed upon.

For the experiments researchers attached radio tags to American cockroaches, Periplaneta americana, to monitor their movements. They were kept in darkness during the experiments and were released in batches of 16 in ‘arenas’ surrounded by electrified wires to prevent escapes.

