Scientists have delivered Scottish tourism its biggest potential boost since Braveheart by revealing a plan to spare visitors the torment of midge bites.

For the first time they confirmed a long-held belief that the scourge of the Highlands finds some people more attractive than others. According to entomologists, it is all down to perspiration, and they are now working towards developing a repellent that will ensure the insects find everyone - no matter what is in their sweat - unattractive.

Dr Sally Singh, of the University of Edinburgh's Centre for Tropical Veterinary Medicine, said: 'We have established for the first time that some people are bitten more than others, and that this depends on the behavioural and electrophysical responses of midges to different people's sweat extracts.'

Singh and her team collected sweat samples from volunteers using skin swabs after putting them through a vigorous exercise routine. They then gave each sweat sample a 'field attractiveness score'. The higher the score the more likely a person is to be bitten by midges.

The research will help entomologists develop new repellents to block receptor sites on midges' antennae and thus stop people being bitten, no matter how attractive their sweat is to the insects. Although there are several species of midge in the UK, Culicoides impunctatas Goetghebuer - the Scottish biting midge - is responsible for more than 90 per cent of attacks on humans and animals.

Singh is also examining how midges' antennae respond to human sweat.