Why Mosquitoes Bite ?

The Scientist's Answer
Chloe's right. The disheartening truth is that mosquitoes bite to make more mosquitoes. Wayne Kramer, an associate professor of entomology at Louisiana State University in buggy Baton Rouge, explains that mosquitoes snack on us — and other animals — to fuel reproduction. Blood is like a fertility drug for these insects.

North America is home to more than 100 species of mosquitoes that vary by habitat, size, and what they prefer to nibble on — mammals, including people; birds; even reptiles and amphibians. One thing they all have in common is that only females bite, and only blood meals are converted to energy earmarked exclusively for egg production. (For everyday metabolic energy, both male and female mosquitoes rely primarily on plant sugars.) In other words, each bite you suffer helps spawn a new generation of mosquitoes, ensuring the disruption of many future backyard barbecues.

While heat, movement, moisture, and color all play a role, mosquito attraction is mostly about scent. Most mosquitoes home in on prey by sensing chemicals, notably carbon dioxide, which we exhale with every breath. If we could just stop breathing, we'd avoid a lot of bites.