Science Questions

How do mosquitoes know when it's night time?

Sun, 10th Apr 2011

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@daiverd asked:

How do mosquitos know when it's night time? Even if the light is on they still insist on biting and biting! AAAAARG!


Well mosquitoes have a body clock just like we do.  They have a cluster of nerve cells in the mosquito nervous system which use a genetic domino effect to keep time.  So one gene turns on, turns another one on, which turns the first one off and turns the third one on, and so on.  This changes the behaviour of the nerve cell which in turn then changes the behaviour of the whole organism.  In fact, this is a phenomenon that was first picked up in the 1970s.  I've got the paper here:  Journal of Experimental Biology:  The Circadian Rhythm of Flight Activity of the Mosquito Anopheles gambiae, the Light Response Rhythm by D.R. Jones, C.M. Cubbin, D. Marsh from Brunel University 1972, that paper was published.  

They found that mosquitoes have a body clock just like us and you can jet lag them.  So basically, itís their instincts just like mice and other nocturnal animals use their body clock to wake them up at night to come and find food.  Itís the best time for Anopheles mosquitoes to come out at night, that's when their body clock wakes them up.  But, not all mosquitoes are the same.  There are some mosquito species that are active during the day, but they are not active at night and I'm thinking of a good example of this, would Aedis aegypti mosquitoes.  They're big, hungry mosquitoes.  They spread things like dengue and they're a real pest because even if you use a mosquito net, you can't protect yourself because they bite people lots of times during the day, so you find it much harder to ward off their attack.  



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@daiverd asked the Naked Scientists: How do mosquitoes know when it's night time? Even if the light is on they still insist on biting and biting! AAAAARG! What do you think? @daiverd, Sun, 10th Apr 2011

I know this may sound a little odd but mozzies are attracted to the carbon dioxide in your breath, among other things.

They don't just bite you when it's dark, but in areas that have a relatively low population density they will be able to home in on you much more efficiently if your in the same place for more then a few hours, like your bed. This might give you the impression they are only seeking you out at night.

Apparently they can sniff you out from over 30 meters away. It's only the females that bite as they need the protein in your blood to produce viable eggs, the males live off plant nectar.

Generally they seem to be most active at dusk and dawn although I don't know why that would be unless it has something to do with the ideal temperature to lay eggs.

Aaron_Thomas, Mon, 11th Apr 2011

I wonder if it's because winds tend to die down a lot around dusk? Geezer, Mon, 11th Apr 2011

Pure genius Geezer, not only winds but thermal activity too, I suppose the last place a mozzie wants to be is a few thousand feet vertical distance from it's food source! Aaron_Thomas, Mon, 11th Apr 2011

Well the main reason of mosquito attraction is the CO2 we breath out and there are other reasons too, like they are attracted to dark places.

swimming goggles protect your eyes from harsh minerals, chemicals, in pools micsteve22, Fri, 15th Apr 2011

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