To be able to pierce our skin and access our blood vessels, mosquitoes have developed quite the complex mechanism. This proves, yet again, that mosquitoes aren’t simple insects. It’s important to note that male mosquitoes don’t bite us. Mosquitoes actually need sugar for energy, so both male and female mosquitoes drink the sugary nectar or honeydew from flowers and other plants.
All of the biting organs are in the head of the mosquito. Only female mosquitoes need blood because it contains proteins that they use to develop their eggs. So, female mosquitoes have the following special mouthparts to be able to pierce our skin and drink our blood.
Mosquito Mouthparts
Mosquito mouthparts (Source: http://wiki.bugwood.org)
Proboscis
The most visible organ in the mosquito mouth is the proboscis. This consists of multiple parts that can only be seen with a microscope. By looking at just the trunk of a mosquito, you might think that this is a single, rigid organ that punctures our skin like a needle, going directly to our blood vessels extracting our blood. But the proboscis is much more complex and contains other parts that female mosquitoes use to access our blood.
Labium
The labium is the part of the proboscis that covers other mouthparts like a sheath. But the labium is not used for puncturing the skin or sucking blood. In fact, it doesn’t even go into the skin. When a mosquito lands on the skin, it uses the labium to touch the surface of the skin so it can insert the other mouthparts into the skin. Inside the labium are two mandibles, two maxillae, one hypopharynx, and one labrum.
Mandibles and Maxillae
Female mosquitoes use both pairs of mandibles and maxillae to pierce the skin. The mandibles have pointed ends and go deep into the skin. Maxillae, on the other hand, have flat ends. The teeth they have on the sides grip the flesh, helping the other parts move deeper inside the flesh.
Hypopharynx and Labrum
The hypopharynx and labrum are two important tubes that pump blood and saliva. Both of these tubes are empty in the middle so that the mosquito can pump liquids through them. The hypopharynx pumps saliva down to the blood vessel while the labrum pumps the blood out of the blood vessel up into the mosquito.
How Mosquitoes Suck Blood
Finding a Blood Vessel
Female mosquitos sense the carbon dioxide, heat, light, and different odors from our skin. When a female mosquito is close to a human, it finds the area where blood vessels are close to the surface of the skin and lands in that area.
Sometimes, if the vessel is easy to reach, the mosquito will instantly bite through your skin. At other times, it can take its time locating a blood vessel under the skin. If a mosquito can’t find the proper place to bite, it may fly away and look for blood vessels that are closer to the skin’s surface.
Accessing the Blood Vessel
When a female mosquito has found a blood vessel, it inserts its proboscis (more precisely, the mandibles and maxillae) into the skin. After piercing the skin, the parts that do the pumping are inserted.
The mosquito pumps the victim’s blood through its labrum into its abdomen. Mosquito saliva contains anticoagulants. These enter the victim through the hypopharynx and keep the blood from clotting.
A mosquito can suck blood for up to four minutes, not stopping until its abdomen is filled, until the process is interrupted, or until the mosquito is killed.
After the Mosquito Has Gone
After the mosquito leaves, its saliva remains in your body. This is what causes your body to have an immune response that results in swelling and itching around the bite area. Once the immune system gets rid of the substances from the mosquito’s saliva, the swelling and the itching will go away.