We’ve all been woken up at night by an annoying bzzz near our ears. Other than disturbing our sleep, what are the reasons mosquitoes buzz? And how a tiny can insect make noise too strong ? Answers.
The mosquito, small but very noisy
The mosquito belongs to the order of diptera and the Culicidae family. There are more than 3,500 species around the world, 105 in Europe and 67 in France. Their cut is between 0.5 cm (for Aedes albopictus or tiger mosquito) and 3.5 cm (for Toxorhynchites speciosus). Measuring 1.5 cm, the Culiseta longiareolata is the largest mosquito inEurope. Diptera weigh 2.5 to 10 milligrams depending on the species. You should know that only the female stings and, once engorged with blood, her weight can triple. Sexual dimorphism is reflected in particular by a hairiness more important in the male with shaggy antennae. As for the female, she has a long and thin deceived rigid (rostrum) of the pricker-nozzle type.
Madam mosquito, the loudest
The throbbing noise is emitted by the female, that of the male being more deaf. Its high-pitched whirr aims to invite its partners to a parade bridal and musical. When his presence is signaled, that the meeting has taken place, the couple can form. After mating, the buzzing female stings humans because the blood meets a need for proteins that promote the maturation of its eggs. The future mother acts the night, especially at dawn or dusk, while we are sleeping. If nothing bothers her, she takes her blood sample in just two to three seconds. During the bite, the female injects saliva anticoagulant which causes a more or less important inflammatory allergic reaction causing a red pimple to appear and itching.
An energetic and strident beating of wings
The mosquito makes its noise in flight, flapping its wings between 400 and 2300 times per second, which is four times faster than all other insects of the same size. This ultra-fast vibration causes the famous sound acute, so unpleasant to our ears. Why does the Diptera spend so much energy flying? Because he is small and lightweight. A study carried out in 2017 by British and Japanese biomechanics specifies the mechanism of the flight of the mosquito. The observation was made using infrared radiation and cameras capturing 10,000 frames per second from all angles. The experiment made it possible to dissect plane by plane the beating of the wings of the animal (below).
The flight of the mosquito, brilliantly resounding
As in most flying insects, the wing movement of descent of the mosquito causes a vortex over the part before wings. This dynamic produces a difference of pressure which itself generates a lift force pushing the animal towards the high. However, this process is not enough to keep in the air the small mosquito which however found a ingenious parade: at the end of each descent and each ascent, its wings rotate and rise upside down to continually line up in their beats and stay at an altitude stable. According to scientists, most of the forces aerodynamic that carry the weight of the mosquito is generated in a way that has never before been observed in a flying animal.
A couple of mosquitoes in tune
A study by researchers at Cornell University in New York showed a tender curiosity. In the species Aedes aegypti (vector of dengue, chikungunya and yellow fever), the partners synchronize the rhythm of the beating of their wings in order to meet and mate. Usually the frequency wingbeats of a female of this species are established at 400 hertz and that of a male at 600 hertz (one hertz equals one beat). Biologists have noted that when the two individuals move closer to each other, they change immediately the frequency of vibration of their wings which then reaches 1200 hertz, that is to say twice the normal pace of the male and three times that of the female. So, behind the shrill hum that haunts our nights is in reality hiding a harmony settled like music paper!