The word proboscis, the name for the long, penetrating, blood-sucking mouth part of a mosquito, doesn’t have anything to do with the word “probe.” But after watching this video shared by science journalist Ed Yong of what a mosquito’s mouth does while it’s inside you—wiggling, writhing, searching around for a blood stream to suck—you’d be forgiven for guessing that’s where it came from.
It’s easy to think of a mosquito’s mouth as a needle, lancing your flesh to find a drink. Under your skin isn’t just an ocean of blood, though. The red drink the mosquito is after is segregated off in blood vessels. For the mosquito to take a sip it needs to find it first. Hence the probing, exploring proboscis. Here’s Yong describing the video:
This footage was captured by Valerie Choumet and colleagues from the Pasteur Institute in Paris, who watched through a microscope as malarial mosquitoes bit a flap of skin on an anaesthetised mouse. The resulting videos provide an unprecedented look at exactly what happens when a mosquito bites a host and drinks its blood.
Mosquitos’ mouths are made of multiple parts, says Yong: Some are sharp and help with the piercing, while others, like the two seen wandering around, are flexible:
The large central needle in the video is actually two parallel tubes—the hypopharynx, which sends saliva down, and the labrum, which pumps blood back up. When a mosquito finds a host, these mouthparts probe around for a blood vessel. They often take several attempts, and a couple of minutes, to find one. And unexpectedly, around half of the ones that Choumet tested failed to do so. While they could all bite, it seemed that many suck at sucking.
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