back to article Female blood-suckers zero in on human prey by smelling our breath

Deadly female blood-suckers have been shown to zero in on their living prey by sniffing out the CO2 emitted in exhaled breath, according to new experiments. The blood-drinking femme fatales in question are mosquitoes: but in all fairness mosquitoes are probably more of an issue for the human race than sexy vampires on any …

  1. iLurker

    Not convinced.

    If this was true mozzies would be primary attracted to the head - or near to it. Possible perhaps if the victim is lying in bed covered in bedding.

    But in Australia at least this doesn't explain why mozzies have a clear preference for exposed ankles and feet if these are available, not the face or head.

    1. Anonymous Coward
      Anonymous Coward

      Re: Not convinced.

      The CO₂ is a long-range detection mechanism. They use sight and warmth at close range. All this is already ancient news so I'm wondering what exactly the news angle is... None of it explains the antipodean foot fetish thing though. Presumably they're trying for your arms and face like normal mozzies but get confused by the fact that you're all standing upside-down.

      1. GBE

        Re: Not convinced.

        "All this is already ancient news"

        That was my reaction. We've known they are attacted to CO2 for ages. That's why people buy propane powered CO2 generaters to put in the far corner of the back yard to draw the mosquitos into traps.

        1. Grikath

          Re: Not convinced.

          you all forgot smelly feet...

          That one was good for an IgNobel award...

        2. Hud Dunlap

          Re: Not convinced.

          Even the mosquito magnet uses two different attractants depending on region of use. Ther is more to this than just CO2.

    2. Dan Paul

      Re: Not convinced.

      Exposed ankles and feet have many veins and arteries near the surface (and little hair), thus the resulting heat will attract mosquitos to them before they reach the head where both CO2 and heat are present. Skeeters stay in the grass until they find a victim and feet are closer to where they roost.

      My diabetic girlfriend however is a target for skeeters as they will prefer her over me anytime we go camping. Since there is a higher sugar level, her blood would seem more attractive to the nasty buggers.

      1. Triggerfish

        Re: Not convinced.

        Yeah thats what I thought as well, but I'd also say they ankles are often more exposed, if out at night somewhere hot often have long trousers on, and also if you are sleeping under a mossie net, or have some sort of blanket then its usually your ankles that are exposed or tangled in the edge of them, easier for the buggers to get at.

    3. Anonymous Coward
      Anonymous Coward

      Re: Not convinced.

      Because contrary to popular belief, the head is not normally the warmest exposed part, especially if you have a lot of hair.

      I tend to get bitten on the back of the neck.

    4. Voland's right hand Silver badge

      Re: Not convinced.

      They navigate by CO2 until they get a lock on via IR and smell from a number of body chemicals in sweat. That is well known.

      As far as CO2 plumes + IR go, a candle (without any chemicals added) is capable to spoil their lock-on abilities quite a bit.

      That is the real reason for all those candles and oil lamps in the outdoor cafes around the Mediterranean. Some places use scented (or laced with repellent) ones, though frankly there is bugger all difference. A naked flame by itself is more than sufficient to do the job.

  2. Your alien overlord - fear me

    Here's my idea

    Put a manakin between mossie base camp (river) and village. Paint said manakin in black treacle (black to absorb the heat better, treacle to trap the mossies). Now, get some nerdie techo-boffin to rig up a CO2 source (should ber self-sustaining, no electricity needed) to entice mossies to it, they see a bloke, move in, feel the heat and go in for the kill.Oh, it's them who die. Hey presto, no mossies.

    Now, should I put this out on Kickstarter or IndyGoGo ?

    1. Anonymous Coward
      Anonymous Coward

      Re: Here's my idea

      So we just need lots of things emitting hot CO₂ that's laced with poison?

      Dump the hybrids, fire up those supercharged V8s!

    2. Robert Helpmann??

      Re: Here's my idea

      Now, get some nerdie techo-boffin to rig up a CO2 source (should ber self-sustaining, no electricity needed)

      You mean something like a TiO2 coating? Perhaps a magnifying glass and a lump of charcoal would work better.

    3. cyfahead

      Re: Here's my idea

      I can feel a design coming on..... Eureka!!!

      Black cement, anthropomorphic compost digester!!!

      Stand them up, holding hands, all around the village... a 'mosquito boma'.

      Just copy those strung out along Crosby Beach near Liverpool, call it a 'Bill Boma' and ask the Gates Foundation to support it!!

      Just don't let on to Mr Gates (... until he has spent the money) that the "Bill" puns in on Bill Crosby (....get it?) and not his lordship!

  3. This post has been deleted by its author

    1. Richard Taylor 2

      Don't flatter yourself - they are just checking you are breathing

      1. Captain DaFt

        Or checking to see if you're soused enough to take a two for a ten.

  4. Blank Reg Silver badge

    So what's new here?

    This is information we've known for ages, it's the basis for all the co2+heat mosquito traps

    1. Chris G Silver badge

      Re: So what's new here?

      Agreed, very old news. We knew this in the army in the 70s.

      One of the reasons troopers smoke so much, when sitting in a mozzie infested forest, the carbon monoxide confuses the CO2 signature and the little buggers dont like the smoke.

      A tube of Autan bug repellent a night would help if only because we plastered it on so thickly they couldnt get through it.

    2. Sir Runcible Spoon

      Re: So what's new here?

      I was thinking that too - how come I've known this for years yet there is new research to 'prove' it. I certainly didn't do any experiements so I must have read it somewhere (and it was a fair while ago too).

      Perhaps the world is suffering some kind of reboot process where bits of it forget that stuff has already been done (prior to the reboot).

      <awaits BSOD aka 'The Sky' to fall in on me>

      1. David 18

        Re: So what's new here?

        "Perhaps the world is suffering some kind of reboot process where bits of it forget that stuff has already been done (prior to the reboot)."

        Ahah that explains the US Patent system!

    3. Toltec

      Re: So what's new here?

      Is the new bit the visual then heat signature part?

      Possibly feet are more of a visual clue than a head, bare rather than hairy skin, perhaps there should be a study to see if bald people get bitten on the head more often? Once homing in on the feet the heat signature bit has a range of a metre so the head is then out of range?

      1. PNGuinn
        Thumb Up

        Re: So what's new here?


        Hmmm - good Idea. Do you think that would be worth a substantial research grant?

        I can think of a few bald Westminster Weasels we could experiment on...

        1. Antonymous Coward

          Re: So what's new here?

          Westminster Weasels are cold blooded.

    4. VeganVegan

      Re: So what's new here?

      What is new is that they showed that the response is conditional:

      If CO2==true:

      ....Look for visual contrast

      ... If visualContrast == true:

      ........Look for warmth

      ........If warmth ==true


      In the absence of CO2, they ignore visual contrast, warmth.

      In the absence of visual contrast they ignore warmth.

  5. disgruntled yank Silver badge

    another option

    An acquaintance who worked for the Centers for Disease Control long ago explained the CO2 connection. She offered as one possible approach keeping a pig about, since pigs generate more than humans do.

    1. Anonymous Coward
      Anonymous Coward

      Re: another option

      For some reason that strikes me as more than a bit psychotic.

    2. Anonymous Coward
      Anonymous Coward

      Re: another option

      She offered as one possible approach keeping a pig about, since pigs generate more than humans do.

      Any chance she was subtly cracking on to you...?

      1. Triggerfish

        Re: another option

        Pigs are a good host for Japanese Encephalitis (if you are in SEA), which is then spread to humans via Mosquito bites, you can get a jab for it but its not commonly on the list if you go for jabs when traveling abroad.

    3. PNGuinn

      Re: another option

      More what? Enquiring minds etc etc...

  6. Richard Taylor 2

    I live part of the year on an island on the west coast of scotland. The local, and very insidious equivalent is the midge. A number of people (us included) use a device that burns (at a very low level) gas to produce small amount of CO2 luring the little bastards to their death. They work well - you can sit out on the 'porch' with a bbq without being eaten to death. Not cheap at about £300, but worth the investment for the reduction in blood loss.

    1. Simon Harris

      But wouldn't the BBQ provide a bigger CO2 + heat signature anyway?

      1. Richard Taylor 2

        And they burn there too. You don't run the BBC where you are sitting.

  7. Eclectic Man Silver badge


    I am reliably informed, and ahve tried it myself, the product "Avon Skin So Soft" is b far the best cream to prevent mossies, gnats and other blood-sucking insects from biting. It works in the Scottish highlands, athough you do have to spread it all over. It is also used by the Roayl Marines and Canadian lumber-jacks (not just the Monty-Python kind).

    It is quite intersting to see, in the macho hunting, shooting and fishing shop windows, a bottle or two of ASSS coyly snuggling amongst the waxed jackets and shot-gun adverts.

    1. Triggerfish

      Re: ding-dong!

      Yes it works for some not others for some reason, my GF always used to get bitten, whereas I swear by it, you smell a bit girlie but its worth it. I used to just take the shower gel though, then spread a lot of deet based repellent on.

    2. silver darling

      Re: ding-dong!

      With the amount needed, dubious effectiveness and price of skin-so-soft (and making sure you get the right version), it'd be cheaper to napalm your chosen scottish west coast bbq area. Commandos sent to Knoydart armed only with Avon? there would be Brecon Beacons type recriminations

      The wee bams don't like DEET , no-one likes DEET but it is effective ... long term, and to avoid 60's style poisoning, full body nets are the answer ...

      The longer long term answer is SHOOT THE SHEEP and deacidify the environment this type of farming causes and the midges love so much ...

      1. Anonymous Coward
        Anonymous Coward

        Re: ding-dong!

        May I humbly suggest that you go and stand naked in the middle of Rannoch Moor and let the beasties eat you alive. It wasn't the sheep that created the peat bogs where the mozzies breed.

        1. silver darling

          Re: ding-dong!

          True, sheep didn't create Rannoch Moor and many areas of Scotland may well have had midge for a long time ... but sheep farming, compared to cattle farming, acidifies an environment and spreads the peat, and therefore the midge. Stripping out the trees 19/20th century style hasn't helped either.

          Compare midge populations in Norway and Scotland or try and find references to midge pre 19th century. Surprising an 18/19th century English army so quick to bemoan the bleakness of Lochaber forgot to mention the misery of midge, a misery recorded by many modern day tourists.

      2. Dr Dan Holdsworth

        Re: ding-dong!

        Actually, this won't work.

        Only female midges bite people, and they only do so in order to lay a second or third batch of eggs; they can breed successfully without needing to feed as adults, though a good blood meal hugely increases their breeding success.

        Repellents work because there are a couple of systems working in a midge's nervous system; attractant nerves and an antagonistic repellent system. If the former predominates they keep coming; if the latter then they stop and often just start circling. This can be seen with flies on moorland; out mountain biking on moorland, a sweaty biker will always attract a following of flies, which can only catch up to you when you stop, otherwise the airspeed needed is too high.

        Sticking some paper tissue in between the bike wheel spokes and soaking it with DEET means you leave a scent plume of CO2 and of DEET, which confuses the hell out of flies and turns quite a few away.

        On the other hand, if you're going to be sitting in one place, you need stronger medicine. Try one of the US-made midge repellers, which put out a vapour of insecticide. This doesn't kill the insects, just slightly clobbers their nervous systems so they can't fly straight or coordinate well enough to bite you.

    3. Steve Davies 3 Silver badge

      Re: ding-dong!

      Skin so soft works brilliantly on the 'No Seeums' that inhabit places like Sanibel Island in Florida.

      Even a few of the local stores sell it which is unusal for an Avon product which is more often sold via 'Ding dong, this is your Avon lady' sales methods.

    4. Dan Paul

      Re: ding-dong!

      Relatives in the Adirondack Mountains of New York State used to swear by Skin-So-Soft.

      Didn't work for me at all. I see your "midges" and raise you "blackflies". They lay eggs under your skin when they bite you. Festers up something horrible and eventually pops. Some people are allergic the nasty buggers and get skin reactions too. They could make a SciFi channel B movie like "Sharknado" about them and their offspring.

      Nothing but 100% DEET works but you don't want to use that on kids. Better get a fine screen bug net for them.

      The best solution is mass spraying of B. thuringiensis and killing the larvae directly but you can't do that on your own.

      There are literally clouds of the damn things and I have seen farm animals literally go crazy when they are attacked by them.

  8. knarf


    So a fire emits C02 its got a thermal signature so why don't we all just carry a flaming torch, not suitable for fire risk area or while riding your bike

  9. Anonymous Coward
    Anonymous Coward

    Just stop...

    breathing and they will go away!

    1. Anonymous Coward
      Anonymous Coward

      Re: Just stop...

      Did wonder about trying that with the wife who always gets bitten. Certainly would be quieter without her moaning about it.

      But then when she's cold and dead they'll probably pick on me instead :-)

      Think I'll just leave her as live bait....

  10. Triggerfish


    Maybe we should encourage more bat habitats, the average bat eats a lot of insects a night pipistrelles around 3000 a night.

    1. Richard Cranium

      Re: Wildlife

      BATS - the only UK mammal population infected with rabies...

  11. silver darling

    and the vaccines?

    Good to see research in this area but as other commentards note this research is somewhat superfluous. What we need are malaria and dengue vaccines, perhaps when global warming brings malaria to middlesex we'll see the investment needed to create those ...

    1. Triggerfish

      Re: and the vaccines?

      I'm pretty sure there's a lot of work going into these already (not arguing more money would not be good). But there's a lot of countries that are fully aware of the dangers of Malaria on have been trying to come up with solutions better than prophylaxis.

      Dengue fever seems to be getting more common, few years ago no one I knew had it our worried about it too much, now I have a few friends who have suffered more than one bout.

  12. earl grey

    I didn't get past the picture

    What was this all about?

  13. Ironclad

    Hollywood to the rescue.

    Visual camouflage and heat signature suppression?

    Look no further than a thick coating of cold swamp mud, as ably demonstrated by Arnie in the first Predator movie.

    1. Chris G Silver badge

      Re: Hollywood to the rescue.

      In addition to swamp mud, camo face paint helps quite a bit. OK if you're a squaddie on exercise in the woods but so far not socially acceptable, perhaps there's an opening for one of the cosmetics companies to start a summer face and body painting campaign.

      As for malaria reaching Middsex? is it still there?

      I am sure I have read that malaria was endemic in the marshes in the South of England in Roman times.

      1. Anonymous Coward
        Anonymous Coward

        Re: Hollywood to the rescue.

        "I am sure I have read that malaria was endemic in the marshes in the South of England in Roman times."

        Malaria was once endemic in many parts of Europe. It was reported a couple of years ago that a woman in Naples had been infected there - the first case for a long, long time. The genetically inherited condition of Sickle Cell Anaemia is common in the Mediterranean area because carriers are relatively immune to malaria. When the parasite gets into an SCA blood cell then the walls collapse - disrupting the parasite's life cycle.

        A BBC nature programme a few years ago showed a team monitoring some sites in Southern England for the mosquitoes that can carry malaria. They were gloomy about the return of the disease if average temperatures increase even slightly.

        IIRC You identify the potential carrier type when it attaches itself upside down to a horizontal surface. It rests at a 45 degree angle - rather than horizontal.

        1. x 7

          Re: Hollywood to the rescue.

          Malaria was recorded in the Essex marshes in England up until around the first world war - draining to increase food production may have helped kill it off. That was the last recorded place, though anecdotally as a kid I was told "ague" existed on the Somerset levels until the 1950's.

          Certainly in the 1800's "marsh fevers" or ague existed in Somerset, Romney Marsh, Essex, and parts of Fenland and possibly the broads. I''ve never seen records suggesting it existed on the Lancashire or Cheshire marshes - too far north maybe

  14. x 7

    This is not new, and its not original research

    Female mosquitoes being attracted by carbon dioxide in breath has been known for at least 20 years, if not longer. There have even been attempts at traps using CO2 as bait in the past

    Yet another example of someone not checking prior literature before publishing. What gets me though is how often these non-new news stories get picked up by El Reg, there have been several recently.

    1. Charles Manning

      Re: This is not new, and its not original research

      "This is not new"

      But it still got them funding. Mission accomplished.

  15. David Roberts

    Dettol and baby oil

    Introduced to this by an NZ boat skipper who had a huge spray bottle of the stuff. He swore by it because it was dual purpose. Kept the sand flies away and also treated scrapes and allergic rections to sea creatures when emptying lobster pots.

    You do smell a bit strange but it is higly effective and less damaging to clothes than DEET.

    The Wikepedia entry looks a bit doom laden though - basically "also kills cats". Not sure how balanced the entry is (on Wikepedia? Shirley you can't be serious!)

    1. Charles 9 Silver badge

      Re: Dettol and baby oil

      I'd have to look, but you can't take the "also kills cats" as a joke, either. After all, chocolate can kill dogs (it's the theobromine that does it). Different animals, different sensitivities.

      1. Jim84

        Re: Dettol and baby oil

        Is it really beyond human ingenuity to build a device that attracts and then kills mosquitos? Do the bastards adapt to all attempts or something?

        1. Anonymous Coward
          Anonymous Coward

          Re: Dettol and baby oil

          I think part of the problem is that the mosquitos' sensory systems are so well-tuned (perhaps due to evolution and a short life-cycle) that it's basically very difficult to actually trick a mosquito into attacking a trap. Think of it this way. What can you think of, apart from a warm-blooded animal, that emits heat throughout its body, emits relatively clean CO2, is relatively large, and moves? You can get away with simulating the first two (that's how modern CO2 traps work), but making the whole business reasonably large and mobile trips you up which is why it's usually better to just confuse them with candles and chemical repellents.

  16. xehpuk

    If I have a 5m tube for exhaust air?

    Could I then fool them to be out of range for visual and thermal sensors?

  17. Dr_N Silver badge

    The most satifying way of dealing with Mosquitos ...

    ... is The Executioner electric racquet: Burn you bastards!!!!!

    Just wait until the Asian Tiger mosquito makes it to UK shores. I'm sure the Daily Mail must have already printed "stories" about it...

  18. Charles Manning

    But they're repelled by DDT

    Until greenies got in the way, DDT was a real cheap way to deal with mozzies.

    The most effective way to use DDT as a deterrent is to mix a diluted mixture and spray it on the walls of dwellings. That gives months of repellent action.

    Used that way, DDT has no harmful effect on inhabitants, birdlife etc etc.

  19. Anonymous Coward
    Anonymous Coward

    I have the preferred flavour of blood in our household. I'm the one slathered in repellent, in the room with those plug in thingies that emit some kind of (allegedly) toxic fumes and a UV light that (allegedly) attracts them to be frazzled on an electrified grid yet I get bitten while the rest of the household takes no precautions and gets away bite-free.

    Eating Marmite (yeast extract) is supposed to work, of course it didn't so I tried what was said to be the "active ingredient" in Marmite, vitamin B12 at high doses. After a few days that made my skin smell different but that's all.

    I think my attractiveness is related to my body heat profile, I'm the one in a T-shirt when everyone else has so many layers I'd die of heat exhaustion - and of course, less clothing makes it easier for the little buggers to bite.

    1. ZippedyDooDah

      Much nicer than DEET

      "I have the preferred flavour of blood in our household."

      Me too. That's been applicable in several different households of this serial monogamist.

      The most effective repellent by far that I have encountered and used is the regular consumption of Ouzo.

      On arrival in Greece on multiple visits I suffered considerably more bites than fellow travellers. About one week after commencing drinking Ouzo in fairly large quantities, the mozzies left me completely alone. Locals attributed this to one or two things, the odour of the herbs in the drink reaching your sweat glands and acting as a repellent or your blood tasting so repulsive that they didn't get around to injecting the anti-coagulant that causes the irritation.

      As an aside, candles galore laced with citronella were almost useless. Ouzo was cheaper than candles, well in the old Drachma days anyway.

    2. x 7

      "I think my attractiveness is related to my body heat profile, I'm the one in a T-shirt"'

      I take it you're female?

  20. sguykayak

    old news

    We were taught biting (female mosquitos) were attracted to our CO2 back in grade school in the 70s. How in the world can this be 'new' research??

  21. Frank N. Stein

    I'm far more concerned about the sexy female humanoid blood sucker variety. They can be found out in the wild in my City, at night. >:-)

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