You spend a warm evening outside with family or friends, and nobody seems particularly bothered by insects. Then you get home and discover several itchy red bumps covering your arms and legs, while the person who sat beside you barely has a mark. It can certainly feel as though mosquitoes have chosen you as their favorite person.

Surprisingly, there is some science behind that feeling. Mosquitoes don’t select people completely at random. Female mosquitoes, which take blood meals to help develop their eggs, use an impressive combination of signals to locate potential hosts. These can include carbon dioxide, body heat, moisture, sweat, skin chemistry, odor, movement, clothing, and environmental conditions. Some people naturally produce combinations of these signals that certain mosquito species can detect more easily. But what exactly makes one person stand out while someone sitting nearby seems almost invisible? Continue below…