Body hair puts bed bugs off

Posted by Emma Woollacott

Letting your body hair grow could be the best way to avoid getting bitten by bed bugs, say researchers at Sheffield University.

The team plonked bed bugs onto the arms of 29 intrepid volunteers who had one arm shaved and the other left au naturel.

They found that when people had more layers of both the longer, terminal hairs and the smaller, almost invisible ones covering their arms, the bed bugs were forced to travel further to find a good  feeding ground. This made them much more likely to be detected - and squashed.

That, say the scientists, is why bed bugs and other parasites like mosquitoes, midges, ticks and leeches tend to go for relatively hairless areas like our wrists and ankles.

"Our findings show that more body hairs mean better detection of parasites. The hairs have nerves attached to them and provide us with the ability to detect displacement," says professor Michael Siva-Jothy.

"By forming a barrier and providing detection these hairs prolong search time and make detection more likely because the bug has to spend more time clambering over them."

The results, he says, could help explain why we look the way we do, and may help research into how to avoid insect bites.

"If you have a heavy coat of long thick hairs it is easier for parasites to hide, even if you can detect them," says Siva-Jothy.

"Our proposal is that we retain the fine covering because it aids detection and if we lost all hair, even the relatively invisible fine hair, our detection ability goes right down."