HUNGRY bed bugs made a meal out of student volunteers at Sheffield University - to prove humans have natural defences against the pesky parasites.
A group of 29 undergraduates agreed to have one of their arms shaved and the other left as normal.
The bugs were let loose for an unfettered feast - with the hairless arms proving mightily munchable.
The research proves human hair helps defend and detect blood-thirsty invaders on our bodies.
It also explains why people get bitten most on relatively hairless areas like wrists and ankles by midges and mosquitoes while on holiday.
Bed bugs are still a serious problem in many parts of the world - including cities like New York.
The Sheffield investigation discovered sensitive, fine hairs cover our bodies allowing us to feel parasitic insects on our skin as well as creating a natural barrier to stop them biting us.
Shaving the student volunteers showed people with more layers of longer hairs and smaller almost invisible hairs covering their arms extended the insect’s search for an ideal feeding ground which in turn increased its chances of detection.
Professor Michael Siva-Jothy from the university’s Department of Animal and Plant Sciences carried out the research with Sheffield Zoology graduate Isabelle Dean.He said: “Our findings show more body hairs mean better detection of parasites.
“The hairs have nerves attached to them and provide us with the ability to detect displacement. 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.
He added the results could explain why humans look like they do and provide better understanding of how to mitigate the impact of insect bites.