Scientists believe they have found the answer to why some people prove a more tasty meal for mosquitoes than others.

The researchers, from the Rothamsted Research institute in Hertfordshire, wanted to find out why some people tended to be bitten more than other people.

They now think their finding - that some people produce natural mosquito repellents - could lead to new types of insect sprays and lotions being developed.

James Logan, a research student, found that some people gave off "masking" odours that prevented mosquitoes from finding them.

The study, supported by the Biotechnology and Biological Sciences Research Council (BBSRC), followed past research on cattle at the institute which showed that the number of flies around a herd depended on certain cows being there.

They researchers found that these "unattractive individuals" gave out different chemical signals from the other cows.

When these cows were moved to another field the number of flies around the herd increased.

In the latest tests, Mr Logan and Prof Jenny Mordue from the University of Aberdeen, looked at how yellow fever mosquitos behaved when exposed to the odour of volunteers.

The researchers said the results suggested that the differential attractiveness was due to compounds in unattractive individuals that switched off attraction either by acting as repellents or by masking the attractive components of human odour.

Prof Julia Goodfellow, BBSRC chief executive, said there were clear benefits from the research.

"Discovering what makes a person more attractive to mosquitoes presents scientists with the opportunity to develop safe, naturally occurring insect repellent which could be far more effective than conventional products because it relates to the way mosquitoes select their hosts," she said.