Mosquitoes can bite a person multiple times. While one mosquito might deliver several bites, repeated bites in the same area often indicate multiple mosquitoes feeding. Understanding their feeding biology and what attracts them helps explain this.
The Mosquito’s Feeding Process
Only female mosquitoes bite, as they require a blood meal to produce eggs. This blood provides the necessary protein and nutrients for egg development. Without sufficient blood, many female mosquitoes cannot lay viable eggs.
A mosquito’s mouthpart, called a proboscis, is highly specialized for piercing skin and drawing blood. When a female mosquito lands, she uses sensory probes on the tip of her proboscis to find a suitable feeding spot on the skin.
Once located, she inserts needle-like stylets into the skin. These stylets saw through the skin and probe for a blood vessel, while another part draws blood and injects saliva. This saliva contains anticoagulants and a mild anesthetic, which prevent blood clotting and numb the area, allowing the mosquito to feed undetected.
Why Mosquitoes Might Bite More Than Once
A single female mosquito can bite multiple times until she is full, sometimes up to five times. This often occurs if her feeding is interrupted, such as when a person swats at her. If disturbed before consuming enough blood for egg production, she will attempt to feed again on the same host or a different one.
Another reason for multiple bites from one mosquito is if she fails to locate a blood vessel on her first attempt. She may then probe nearby areas until a suitable vessel is found. While one mosquito can bite repeatedly, multiple itchy bumps often indicate that several different mosquitoes have fed, as each bite causes a localized immune response to the injected saliva.
What Attracts Mosquitoes
Mosquitoes locate potential hosts using a combination of sensory cues. Carbon dioxide (CO2), exhaled by humans and animals, is a primary long-range attractant, detectable from significant distances, sometimes up to 50 meters. Mosquitoes use specialized receptors to detect changes in CO2 concentration, signaling a host’s presence.
As they get closer, mosquitoes are drawn to body heat and various chemicals present in human sweat and on the skin. Lactic acid and ammonia, released through sweat, are strong attractants. Skin bacteria also contribute to an individual’s unique odor profile, influencing their appeal to mosquitoes. Visual cues, such as movement and contrasting colors, also play a role in short-range host identification.