An African proverb says: “If you think you are too small to do great things, try sleeping with a mosquito in a room.” And it is that the disturbing sound of a mosquito hanging around our auditory pavilion is enough to not sleep a wink all night.
The buzzing of mosquitoes is due to the fluttering produced by their small wings when flying and is caused by both females and males, although it is true that we usually hear that of the females, since they are the ones that feed on blood human. The males, for their part, usually buzz around the plants, in search of the precious nectar.
When flying, males emit a sound close to 600 Hz, while females emit a sound that is around 400 Hz, the difference is due, in part, to the different size of the wings.
Mosquitoes are capable of detecting the vibrations produced by the resonance of the wings of their congeners thanks to a mechanoreceptor –Johnston’s organ- that they have in the pedicel or second segment of their antennae. The receiver was named after a Baltimore physician, Dr. Christopher Johnston, who first described it.
The mosquito Johnston organelle would be the equivalent of our auditory system and is enormously developed in males compared to that of females. For example, in the case of the yellow fever mosquito (Aedes aegypti), males have more than 15,000 neurons dedicated to capturing and interpreting sounds in that organ, while females have less than half.
In addition, it has been possible to demonstrate that the buzzing of mosquitoes is related to mating rituals. Some scientific studies have shown how males try to “connect” their buzz with that of females and when they succeed, they mate by adjusting their frequencies until they reach 1,200 Hz.
These data, in addition to the pleasure of knowing, can be the basis of future control programs that could help to harmonize their buzzing, avoiding mating and, with it, the transmission of diseases.
Mosquitoes choose their victims
Mosquitoes show a special appetite for some people, who seem to have a powerful magnet capable of attracting their attention, while, on the contrary, there are others who seem to be totally immune to their bites.
In 2004 a study was published according to which people with type 0 blood were up to 83% more likely to be bitten by mosquitoes than anyone with another type of blood group.
Other researchers have discovered that the higher the body temperature of our body, the greater the attraction we generate towards mosquitoes and that even the simple fact of having consumed beer makes us a much more appetizing victim.
Of all of them, perhaps the most powerful factor in attracting dipterans is the emission of carbon dioxide, a gas that can be detected by mosquitoes up to a distance of thirty meters.
It is estimated that, per day, we exhale one kilogram of carbon dioxide, and that every time we expel air from our lungs we emit about 100 mg of this gas, a figure that is higher in adults than in children and that varies depending on the diet and the physical exercise that we carry out.
It seems that it is precisely the emission of this gas that acts as a powerful GPS, allowing mosquitoes to find their victims in the dark of night.