With summer in full swing, many of you are probably growing weary of the high-pitch wine of the mosquitoes and their pesky, itching bites. But next time one of them nips you, have a little respect for their wily ways. A scientific publication has managed to catch mosquitoes in the act – recording their amazing feat, as it happens, from under the skin.
Right from their approach, it’s a remarkable act. As the mosquito comes in to make the landing, it spits out a swab of anaesthetic. That’s why you never notice them. Now senseless to the attack, the mosquito’s head begins forcefully pushing downwards, and as it does, the sweeping long snout – the labium – makes contact with the skin. This sheath-like appendage splays open into two, releasing a torturous apparatus within.
There is not, as you might think, a single proboscis. Instead, there a total of six surgical instruments.
The first pair of these – the maxillae – are tipped with razor-sharp teeth, microsaws that begin tearing through the senseless skin, the head rocking and vibrating, working the needles deeper. The next pair of proboscis – the mandibles – are simple forceps, gripping the skin, holding the incision open, and acting as leverage for the mosquito to drive the final two mouthparts down into the host.
These final two proboscis work as a parallel team, probing down into the skin as a flexible and fully-controllable tool. It is shaped by the sophisticated developments of 100 million years of evolution, easily outperforming the crude microsurgical inventions of mere humans. The end of the proboscis flexes and bends like a miniature trunk, practically twisting at right angles, probing between the cellular structures of the host, pushing deeper as receptors search, sniff, and hone into the chemicals exuded by the pumping blood vessels.
Once the mosquito hits her vein of liquid gold, one of the probing needles – the hypopharynx – spits a cocktail of chemicals into the open wound: more anaesthetic, anti-inflammatories, plus anticoagulants. This thins the blood, letting it flow more easily, and prevents the vessel collapsing. Simultaneously, the other probing needle – the labrum – begins gulping, pumping blood back up. With the right equipment, you can even see blood cells, visibly bubbling up through the opaque mouthpiece.
And it all happens in under a minute.
Just a shame it itches so much.