Mosquitoes use carbon dioxide (CO2) as a primary cue to locate hosts. When a person exhales, the CO2 plume they release acts like a beacon, detectable by female mosquitoes from up to 30 feet away via specialized receptors on their antennae. Once they sense this, they begin flying toward the source, fine-tuning their approach with additional signals like body heat and skin odors.
After detecting CO2, mosquitoes zero in using visual cues, such as clothing color or movement. Studies, like the 2022 University of Washington research, show they’re drawn to longer-wavelength colors (red, orange, black) over shorter ones (green, blue, white), possibly because these resemble host-like targets. This multi-step process—CO2 detection followed by visual and thermal confirmation—makes them efficient at finding a blood meal.