Ever wondered why mosquitoes eat some people up but leave others relatively unscathed? A new study finds that this preferential treatment is due to the smells produced by the microscopic critters that cover our bodies. The research is in the journal Public Library of Science ONE. To a mosquito, every human has a particular smell. And the differences are due in part to the particular bacteria on each individual’s skin. The study tested the malaria-transmitting Anopheles gambiae mosquito's attraction to the odors of 50 adult men. The participants avoided items, such as garlic, that would change their natural smell. Researchers collected the male scents by rubbing glass beads on the bottom of each participant's foot, and swabbed the same skin for microbes. And they discovered that mosquitoes preferred the smell of skin with more abundant - but less diverse - bacterial communities. The scientists suggest that the diverse communities may include some microbes that produce compounds mosquitoes naturally dislike. If further research can identify these compounds, it could lead to the development of repellents to make bloodthirsty mosquitoes buzz off.