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Cockroaches may be one of the most loathed creatures on the planet, but scientists claim they have personalities - and some are even 'shy'.

Experts studying the insects have discovered that they have individual character traits when emerging from hiding places, with some scurrying boldly, while others seek shelter.

The discovery may not make them desirable, it could go some way to explaining the cockroaches' evolutionary success.

Experts studying American cockroaches have discovered that they have individual character traits when emerging from hiding places, with some acting cautiously, and others boldly in search of food (stock image)

In an experiment, scientists from Université libre de Bruxelles studied the behaviour of the insects when they came out in the open.

They theorised that if cockroaches all have the same personalities they would all behave exactly the same when in the open. But their observations revealed clear differences.

Isaac Planas Sitjà, one of the researchers from the university, 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.'

He said that his team is studying the implications of these personalities for social behaviour.

Individual personalities of cockroaches (a microscope image is shown) have an impact on a group of insects. 'Some groups quickly reach a consensus and make a collective decision, whilst other groups with conflicting personalities take longer to make a collective decision,' Dr Sitjà said.

'We are looking for behavioural syndromes that will help to categorise them and give more information about the existing synergies between personality and social behaviour,' he said. 

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.

'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.'

Different personalities are thought to help the survival of the species because by driving different behaviour, at least some of the group is likely to survive if disaster strikes. 

In the experiment, American cockroaches were fitted with radio tags to monitor their movements.

The insects were kept in darkness until they were released in batches of 16 in 'arenas' surrounded by electrified wires to prevent them escaping.

They were measured for the speed with which they found shelter and the time they spent exploring and seeking out new supplies of food.

'Within a group, individuals consistently differed in their rate of joining the shelters and their resting time over the week,' the researchers concluded.

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 on.

The shy insects would be more likely to avoid predators because they spend more time under shelter but would be more prone to going hungry.