What Attracts Mosquitoes?
People have long wondered what attracts mosquitoes. Research has long indicated that mosquitoes are attracted to
odours given off by the prospective host. These are called info chemicals, which are also called semiochemicals.
The mosquito's senses recognize these signals and fly towards them. There are probably two main groups of
attractant odours: human body odour and the smell of carbon dioxide. Carbon dioxide is in the breath that we
exhale, so in this article, we shall concentrate on the body odours. The fact that a mosquito's eyesight is poor,
might help it concentrate on what attracts mosquitoes.
What Attracts Mosquitoes?
A study in Tanzania in 1995, used three volunteers sleeping in three separate tents in an attempt to find out
what attracts mosquitoes. All the volunteers were of a similar weight and age and therefore likely to exhale a
similar volume of carbon dioxide.
However, one of the volunteers proved to be a lot less attractive to the mosquitoes than the other two. Another
test showed that Anopheles bit the feet of victims more frequently than other body
The conclusion was that mosquitoes in general are attracted to certain smells that we give off and that the
Anopheles is more attracted to feet, which has been tested with Limburger cheese, the smell of which chemically
resembles human feet. Another, a follow-up test used worn socks to attract mosquitoes into traps.
Lactic acid is a product of muscle exertion. We are unable to detect it but, tests have shown that mosquitoes
use it to detect prey. Another test continuously pumped a tent full of carbon dioxide, while a human volunteer lay
in a nearby tent.
Far more mosquitoes were trapped in the tent with the human, indicating that body odour is a more significant
attractant to mosquitoes that exhaled breath.
Despite this evidence, the attraction of mosquitoes to a source of carbon dioxide remains the best understood.
It is likely that CO2 is an attractant in its own right, but that it enhances other odours that attract a mosquito
even more - it is possibly a long range attractant, but body odour guides the mosquito into its target.
Octen-3-ol is given off by cattle and is a powerful attractant to many species of mosquitoes. Octen-3-ol is used
by some bug zappers to supplement the attraction of the black light, which is used to lure mosquitoes and other
bugs to their deaths on highly charged electric wiring in garden appliances. Octenol significantly increases the
catch of mosquitoes in the field.
Relative humidity also seems to have an effect on how effective a mosquito's sense organs are. Conditions of
rising relative humidity are the most conducive to a mosquito finding a host.
Research is being carried out into the gasses given off by the microflora that lives on our skin. Our skin is
inhospitable to all but a few types of microflora and the proliferation of these microflora depends on skin
temperature, humidity, PH and the amount of inhibitors and nutrients.
This suggests that a clean skin is less attractive to mosquitoes than a sweaty one. Therefore, if you think that
you are a target for mosquitoes, try showering before going out and before going to bed.
You cannot get rid of microflora completely and neither is it desirable, but you can keep the amount to a
minimum. The real answer to the question what attracts mosquitoes is subtly hidden in the above research but the
truth is that still no one knows really knows what attracts mosquitoes in toto.