The mosquito's host-locating mechanism is a sophisticated multi-sensory navigation system.
The first signal is carbon dioxide—mosquitoes can sense minute changes in CO2 concentration from up to 30 meters away and track the source upwind.
The second signal is body heat and humidity—the human body's surface temperature creates a thermal signature against the surrounding environment, and mosquitoes use infrared heat sensing for precise localization in the final few centimeters when approaching a host.
The third signal is body odor—bacteria on the surface of human skin break down sweat, producing various volatile compounds; each person's "odor fingerprint" is unique.
Scientific research has confirmed that people with type O blood are about 83% more likely to be bitten by mosquitoes than those with type A blood; pregnant women are more attractive to mosquitoes than non-pregnant women (slightly higher body temperature + exhaling more CO2); and people who have just exercised (elevated body temperature, higher CO2 output, and increased lactic acid concentration in sweat) are also priority targets for mosquitoes.
Understanding these mechanisms helps in formulating personal protection strategies—wearing long sleeves and long pants during high-risk periods, using DEET-based repellents, and avoiding outdoor activities at dusk and dawn.