Mosquitoes are attracted to many things. One of those things is carbon dioxide. However, when they flock to it, it’s not really the carbon dioxide they’re after. Instinctively, mosquitoes realize that where there is carbon dioxide, there is an animal host. This is important for female mosquitoes particularly, as they are the only ones that need blood. Females need the lipids in the blood for egg production and so, they search out carbon dioxide knowing a host will be nearby.
It’s for this reason that mosquitoes are attracted to a person’s breath. When humans exhale, they release a lot of carbon dioxide. So, although it may seem like mosquitoes are attracted to the actual breath, it is the carbon dioxide that signals there is blood nearby, which is what they are after.
It’s for this reason that sometimes, people find they attract more mosquitoes shortly after exercising. With more breaths being exhaled at that time, they are releasing more carbon dioxide. As such, they are a larger mosquito magnet.
Once a mosquito has detected the carbon dioxide, they will then use heat to determine where the blood is closest to the surface in the body. The most common areas include the forehead, ankles, neck, and elbows. Those that have just finished exercising also have blood closer to the surface throughout their entire body. As such, they make for an especially optimal feeding ground for mosquitoes.