Cockroaches know what they are talking about

Call me a cycnic who finds TV chesf about as appealing as cockroaches - but at a time when we are facing a plague of cooking programmes, I was intrigued to see that cockroaches recommend good food sources to each other by communicating in chemicals, according to scientists.

The much-maligned insects appear to make a collective decision about the best food source. Who needs a good food guide when you can transmit chemical messages?

The study, carried out by a team from Queen Mary, University of London, helps explain why the creatures are often found feeding en masse in our kitchens late at night.

It was published in the journal Behavioural Ecology and Sociobiology.

Dr Mathieu Lihoreau from Queen Mary’s School of Biological and Chemical Sciences led the research. He pointed out that people tend to “kill cockroaches rather than study them”.

“I can understand that,” he told BBC News. “But it means we don’t know very much about their behaviour.”

It was generally accepted that the insects foraged individually, “but that’s definitely not true,” said Dr Lihoreau. “Anyone who has cockroaches in their home will tell you that’s wrong – you see them in groups.”

To test his suspicion that the creatures were in fact communicating with each other, he and his colleagues gave a group of cockroaches a food choice test.

“We released them into a small arena where there were two identical food sources,” he explained. “If they didn’t communicate, we would expect that they should just distribute on the two food sources equally.”

But the majority of the hungry cockroaches (Blattella germanica) fed solely on one piece of food until it was all gone.

By following individual insects, it also emerged that the more of cockroaches there were on one piece of food, the longer each one would stay to feed.

The hungry insects appear to make a collective decision about what to eat

“We don’t know how they communicate, but we know they’re using chemicals,” Dr Lihoreau explained. “That will be the next step – to find the chemicals involved in the communication.