Ugh, summer. Step outside for thirty seconds and a horde of mosquitoes descends to make you into dinner. But what exactly happens when a mosquito alights and takes a deep drink of you? Some intrepid researchers decided to check it out on the microscopic level, and what they found was actually pretty cool. Also gross, but cool.
You might think of the mouthparts of mosquitoes as a solid needle that penetrates the skin, hits a blood vessel and sets to work, but it turns out that the truth is more complicated. First of all, there are multiple parts involved, including two mandibles and two maxillae to help the mosquito penetrate the skin. Then, the insect uses the hypopharynx to push saliva into the body of the host, preventing clotting and limiting inflammation. The actual sucking involves the labrum, which can sometimes pull blood so vigorously that it ruptures the blood vessel, creating a small pool of blood that the mosquito will freely lap up.
If you think this is creepy and gross, wait until you see the mouthparts of a mosquito in action:
That little wriggling brown thing with attached filaments is the mouthparts of the mosquito, maneuvering for a blood vessel. As you can see in the video, mosquitoes can adjust the angle, bend, and wriggle to find a food source, and they’re also capable of pulling back and going in a different direction. In other words, rather than landing and getting one shot, they have some time to get into position.
This particular research was conducted as part of a study to understand how malaria is transmitted, with the ultimate goal of reducing the incidence of malaria in parts of the world where it’s endemic. None of the information in these videos provides direct clues on how to prevent malaria, but it does offer new data about how mosquitoes do their dirty work, and that information may be helpful in the long term. It’s certainly made for some truly fascinating, albeit deeply creepy when you realize what’s going on, videos.
The next time a mosquito lands on you and you move to brush it away, imagine what’s happening on a cellular level as its mouthparts push through your skin in search of a vessel, and marvel at the complexity of evolution. Mosquitoes have evolved to thrive alongside mammals of various sizes, using them as a steady food source on legs, and that’s pretty amazing. A tip of the hat to nature is definitely in order even though mosquitoes and other biting insects are obnoxious.
In case you’re wondering, these researchers weren’t quite daring enough to serve as their own test subjects, not least because they were using malarial mosquitoes for the experiment. Unfortunately, anesthetized mice were used, raising some tangled questions about the ethical issues surrounding the use of animals in scientific research. Is it worth it if humans benefit? Is it never acceptable? Does it depend on the nature of the research and the conditions in the laboratory?
Photo credit: Filiford.