Scientists have identified the gene that makes mosquitoes crave human blood

Nov 20, 2014

Image: Lesley Scott/Flickr

By Neha Karl

Female mosquitoes that spread dengue and yellow fever didn’t always rely on human blood to feed their eggs – in fact, their ancestors fed on forest animals such as guinea pigs and horses. But thousands of years ago they recognised a distinctive human odour called sulcatone as a source of food, and switched from feeding on furry forest animals to sucking the blood of people, a new study has found.

To investigate the evolution of this attraction, researchers from Rockefeller University in the US looked at the genes of two mosquito species with different diets – the black Aedes aegypti formosus mosquito, and its light-brown cousin, Aedes aegypti aegyptiA. aegyptiformosus prefers human blood, and has managed to spread yellow fever, dengue, and chikungunya viruses throughout the world. A. aegypti aegypti on the other hand, lives in the forest and prefers to feed on forest animals.

The team decided to crossbreed the two species to create thousands of genetically diverse grandchildren. They then separated the mosquitoes based on their preference for forest animals or humans, and compared the genes of the two groups. The results identified 14 genes that were strongly linked to liking humans, but one odour receptor gene – Or4 – was particularly active in the mosquitoes that crave human blood.


 

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13 comments on “Scientists have identified the gene that makes mosquitoes crave human blood

  • But thousands of years ago they recognised a distinctive human odour called sulcatone as a source of food, and switched from feeding on furry forest animals to sucking the blood of people, a new study has found.

    Channeling Stars Wars, “The Sulcatone is strong in me.”

    If I am bitten by a mosquito, it is seven days of itching hell. What was Noah thinking. Even with military grade DEET, I still get bitten. People who I don’t know, invite me to outdoor functions knowing their guests will be safe from mosquitoes. It doesn’t pay well enough however.

    On our major river in Australia, the river Murray, there is a tourist industry of cruising house boats. This gave me a chance for a reasonably controlled experiment. 8 people on board. Night time. All of us up on the roof cruising deck spotting satellites and meteors in the brilliant clear Australian skies. We were in a line. I was third from the right. Over an hour period, I received 7 mosquito bites. None of the other seven got bitten.

    I’ve sat outside at social events with half a dozen mosquitoes buzzing me and no one else aware of their existence. I now wear baggy long sleeved shirts and pants, socks, shoes, a hat, and if it was socially acceptable, I would add on a beekeepers hat and leather gloves.

    I’m suing Noah.

  • Mosquitos prefer type O blood. They like fat people because they exude more CO2 and other volatile chemicals.

    Humans are a good host because they don’t have hair blocking the skin. They sleep soundly. Their hide is fairly thin.

    People who camped out in Northern Canada told me there are even worse beasts than the mosquito. Some take chunks of flesh when they bite.

    I saw a documentary about how mosquitos kill moose and cariboo, simply by overwhelming them and drinking them dry. How monstrous a god to condemn innocent cariboo to such a fate.

  • Some mad but satyrical scientist will insert this blood sucking gene into the genome of a Republican, accelerating the inevitable evolutionary outcome by a generation or two…

  • 4
    Light Wave says:

    At least in Britain we are free from mosquito’s but I’m still scratching 12 years of mossie bites from being in Australia 5 years ago and hey I’m not fat either ….Mossies leave a nasty chemical on the skin in the bite to stop the cut healing too fast…..Here in Scotland Midges are annoying and you don’t even see them, I’m not sure they carry disease like mossies do….But you sure know all about it if they’ve bitten you….its so itchy

  • 5
    NearlyNakedApe says:

    People who camped out in Northern Canada told me there are even worse beasts than the mosquito. Some take chunks of flesh when they bite.

    You probably mean horse flies. Some people call them deer flies (in eastern Canada) or stouts (in Newfoundland and Nova Scotia) or frappe-a-bord (in Quebec). They relentlessly hound you and buzz around your head while you’re trying to escape them. And when they land on exposed flesh, you don’t feel it (unlike regular flies) until you get bit.

    They are incredibly annoying, nasty little blood suckers. The only places you can be safe from them is indoors or on a boat in the middle of a lake. But as soon as you come back to shore, they’re waiting. And if by chance you have caught some fish, the smell drives them nuts and they will follow you for miles.

    BTW, this is why moose and caribou often swim long distances across lakes: to get away from the mosquitoes.

  • David R Allen Nov 20, 2014 at 6:06 pm

    Over an hour period, I received 7 mosquito bites. None of the other seven got bitten.

    It is well known that walking beside someone who the mossies or midges prefer, gives protection!

    http://www.futurity.org/better-traps-are-bad-news-for-mosquitoes/

    Those cunning researchers are trying to find chemical attractants to lure the little blighters into traps.

    I did hear of a Scottish method of using buffalo sweat as an attractant next to a vacuum pipe which sucked them into a bag, for use in hotel gardens, – but I can’t find a link to it.

  • Light Wave

    .Here in Scotland Midges are annoying and you don’t even see them, I’m not sure they carry disease like mossies do….But you sure know all about it if they’ve bitten you….its so itchy

    More than annoying in my experience, and midges are a form of mosquitoes. If they’re out, then I’m in. The perfect summer’s evening spoiled by 50,000 potentially blood sucking insects, all female of course. I remember well a hill walk on the Isle of Arran, where even up high, the air was so still, the midges would be everywhere. No nice happy sandwich at the top, the bar-stewards were swarming everywhere. A brief glance at some rock climbers on the Rosa Pinnacle, made me glad that I could out pace most midges even though the going was hard !

    Scotland’s secret weapon, and the original Loch Ness monsters.

    (And pretty much any other Scottish loch). I have heard, from a local that the Aberdonians are too mean to give blood, but I suspect that being an east coast city, the climate is less kind to the little devils. Certainly they thrive in Inverness, slightly north of Aberdeen, but more to the west.

    There are zappers that you can buy from camping shops and the like which will, given a few clicks, stop the itching. A lump of ice on the bite, or quick immersion into cold water also seems to help. In the case of horse fly bites (clegs), that is quite important as the bite could last for several days, and stands the risk of going septic if scratched too much. Of course it won’t nullify malaria or Nile disease.

  • You probably mean horse flies. Some people call them deer flies (in eastern Canada) or stouts (in Newfoundland and Nova Scotia) or frappe-a-bord (in Quebec). They relentlessly hound you and buzz around your head while you’re trying to escape them. And when they land on exposed flesh, you don’t feel it (unlike regular flies) until you get bit.

    That’s Canada crossed off the tourist list for me… Sounds like the Hannibal Lector’s of the insect world.

  • At least in Britain we are free from mosquito’s

    When I was touring Ireland I was frequently told the story that there are no Mosquitoes in Ireland. Heaven. Filled out my application for citizenship. However.

    In an B&B on the west coast, lights out. Buzzzzzzzzz. I KNOW THAT FREAKING SOUND. Lights on. Close the window. Kill four of the bastards after ten minutes searching the room. Smashed them on the wall. (Cue maniacal screaming) Threats of divorce. I hate to think what the landlady had going through her mind. I photographed two of them. I also photographed my itching welts 3 days later.

    The B&B wasn’t very good. Old soap in the shower. Pubic hair in the plug hole. etc. So I gave it a less than perfect write up and included a reference to the mosquitoes, and to keep the windows closed. I was challenged by the landlady who was none too pleased that I hadn’t given her 5 stars. She vehemently denied the existence of mosquitoes in Ireland. I directed her to the corpses of the four carcases squashed on her wall. I posted photos of the bodies and my welts. I know a mosquito when I see one. It’s an internet myth that Ireland doesn’t have mosquitoes. I had lots of support confirmation. I don’t know about the UK. I did tour north and western Scotland in September and didn’t have any trouble with midges.

  • 10
    Light Wave says:

    Wow Ireland is a bit further south from Scotland and warmer, so I suppose they might get mossies… wow I didn’t know ….and yeah I know how you feel I’ve never felt like killing a creature till Aussie Mossies….Other creepy crawlies I could catch and put outside….But yeah Scottish Midges are like a cloud of invisible miniature mossies lurking in the heather…they get through the finest mesh

  • 11
    Light Wave says:

    Mr Darcy Oh yeah that sounds funny about Arran…I too run away from midges…its the only way to loose them for a second or two but no chance if I’m in a tent overnight….wake up – spotty dotty…and horse flies geez they hurt….

  • Mr DArcy is working on a new recipe to be published on Jamie Oliver’s website : Tsetse Fly Risotto with locust pate, garnished with dried midge !

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