Walkers in Scotland are often targeted by midges
A study which tested the response of midges to human perspiration suggests that the type of chemicals found in the sweat influences the targets chosen by the insect.
Dr Sally Singh, of the University of Edinburgh's Centre for Tropical Veterinary Medicine, also examined the way midge antennae responded to human sweat.
She 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."
Insect swarm
Scientists are now working towards developing a repellent that will ensure everyone is unattractive to midges.
Dr Singh hopes her research will help entomologists - scientists who study insects - develop a repellent that can block receptor sites on midge antennae.
There are several species of the insect in the UK, although Culicoides impunctatus Goetghebuer is responsible for more than 90% of attacks on humans and animals.
The tiny insects, which are most prevalent in the west of Scotland during the summer, swarm around their victims and leave loads of itchy bites.
Dr Singh and her team made volunteers exercise for 15 minutes then collected sweat samples using skin swabs.
Midge antennae
They then tested how attracted the midges were to different sweat samples and gave them a "field attractiveness score". A person was more likely to be bitten by midges if they recorded a higher score.
Dr Singh also looked at the way the midge antennae responded to human sweat.
"The insect's antenna is its 'nose' and by making recordings from the sensory hairs on the antenna we can determine whether or not they can detect a particular sweat extract or chemical," he said.
"A midge has approximately 500 sensory hairs on its antennae and these respond to different classes of chemicals."
Dr Singh will reveal full details of her findings at the Royal Entomological Society's meeting in Aberdeen next week.