Mossies really do like YOU!!

No doubt everyone has heard or some may have been guilty of saying, “I don’t know my but mossies and midges seem to love me”. At the same time many of us are probably guilty of thinking that it’s rubbish and said person was just whining.

Turns out they were right all along (apologies to all those I unsympathetically scorned for fairyness). Not sure if this fully applies to midges but the following things do apply to mosquitoes, however midges do bite to obtain blood from mammals so I would guess this they would also have these abilities.

So it seems mosquitoes are not just crazed blood suckers but rather selective in their meal choices. To begin with they use heat and co2 emissions as primary detectors, obviously if your breathing and warm you will have tasty blood. This means that as we are all unique, those of us who either run hotter or breath more are better targets (downside of not feeling the cold). This also applies for temporary changes such as pregnant women (natural body temperature increase), and overweight folks (weaker cardio vascular systems means more huffing and puffing thus co2 production).

But it doesn’t end there, no no it is much worse than that. So most of us know what lactic acid is and that any form of excercise produces it, but tiny amounts of it can be produced in your sweat and the biters can smell the stuff. This way they now know you are breathing, warm, and moving so more likely full of blood. So do you try to claim your idle shuffling pace at the back is actually a stealth mode to deter mossies or burn out trying to outrun the buggers?

In addition they can smell something called octinal which we produce from fatty acids. So had yourself a nice fry before hitting the hills? Great your a walking smelly lunchbox for them now.

Ok now the kicker which will also produce cries of “I told you so!”. We all have antigens in our blood which are kind of like markers for you blood. They can serve as one way to tell what blood type you are, around 80% of humans also secrete tiny amounts of antigen within their sweat and biters can smell this too. Studies have shown that those of us who are sweating this stuff get hit more than those who do not (understandable as it would be another flashing light for a mossie that this ting is even more likely full of blood). But the stinker is for an as yet unknown reason, of the 80% who sweat antigens it is blood group O who are favoured by mosquitoes. So if your an O your kinda screwed and its your dna to blame.

While there has been no proof of why they favour group O I do have a couple of ideas. Firstly O is a very common group and so having a nose for it would mean you can find the most plentiful food supply, which would be handy. Also O is the group which is highly valued for it’s ability to be given to anyone as it does not conflict. Perhaps some mossies have an allergy or something to other blood groups and so O is the safe food. But O also does not have any antigens and so would give of a very unique smell I would guess. This could be a final red flag to a mossie that the thing it is smelling is now 100% prime beef.

Next time your getting mauled while your fellows are bite free and laughing, remember to point out that it is genetic and your are 5 star michelin, while they are all maccy d’s.


Quick correction to this as it effects the theory. Blood group O does not have any antigens and thus do not secrete them in sweat, but they do secrete saccharides which are types of blood sugars. Thus you are a walking nectar machine for mossies. It makes more sense now that they can target group O much more effectively.

Original post was here. With thanks to Rich.H.

This entry was posted in General Outdoors.

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