Tall men and women with a high body mass index are more likely to be bitten by midges, experts said today.
Researchers studying the feeding habits of the Scottish biting midge said bigger people were more likely to be attacked because they "provide a more substantial visual target" for the insects.
Midges are also found in greater numbers at increasing heights - meaning tall people are more likely to be bitten.
The study, by the University of Aberdeen and Rothamsted Research, also suggested children may inherit a tendency to be bitten from their parents, and that women were more likely to react to insect bites than men.
The survey-based study was carried out at the 2008 First Monster Challenge - a 120km duathlon on the shores of Loch Ness in the Highlands.
They asked "hundreds" of competitors about their bites in the largest investigation of its kind for any biting insect.
Professor Jenny Mordue, retired professor in the Department of Zoology at the University of Aberdeen, who led the study, said: "The setting around the shores of Loch Ness is classic midge territory.
"The preference for the insects to target taller people could be associated with midge behaviour and flight patterns, as midges are found at great numbers with increasing height, particularly between one to four metres.
"Larger people would provide a more substantial visual target for host-seeking midges as well as greater amounts of heat, moisture and attractant semiochemicals, such as carbon dioxide, which encourage midges to bite."
The peak midge season in Scotland is between June and September.
It is estimated that in some parts of Scotland, one single hectare of land may host up to five biting midges for every man, woman and child in Scotland - or 25 million biting midges per hectare.
The survey was part of a much larger study to develop new repellents for biting insects.