A chemical chastity belt that stops female fruit flies from cheating on their partner could be used as a weapon in the global pest control war, Norfolk scientists said today.

A chemical 'chastity belt' that stops female fruit flies from cheating on their partner could be used as a weapon in the global pest control war, Norfolk scientists said today.

Scientists at the University of East Anglia (UEA) have discovered a protein in male fruit flies that makes the females they mate with less likely to pair off with rival males.

The protein called PEBII is part of a so-called 'mating plug', which the male leaves in the female reproductive tract after mating. The plug forms a physical barrier and deters other males.

Dr Tracey Chapman, who is leading the study at UEA's school of biological sciences, said: 'Mating plugs act like a sort of chastity belt. We think the PEBII has a subtle but significant role in stopping females pairing off soon after mating.'

Reported in the Journal of Insect Physiology, the work aims to provide new techniques to improve control of insect pests - the source of the some of the world's most serious agricultural and health problems.

The research will continue next year following an award by the Biotechnology and Biological Sciences Research Council (BBSRC) of more than �350,000. It will be the first investigation of the complete pathway by which males respond to rivals.

Many species leave mating plugs in the female reproductive tract after mating. But in the fruit fly, earlier research had shown that the physical presence of the plug itself was not enough to stop females mating again.

Dr Chapman's team discovered that the presence of PEBII was essential for the plug to work properly.

'We noticed that male flies that could not make this protein were not very good at preventing their recent mates from mating again. So we had a hunch that this protein must be really important in the male's mating strategy.'