30 March, 2019 - 08:00 (Research Matters)
Most of us see mosquitoes as blood-sucking pests and wonder if the world would be a better place if there were none. Do they have anything good to offer apart from giving us itchy rashes and deadly diseases? Yes, says science.
Studies on mosquito ecology by people driven by the same curiosity indicate that mosquitoes are, in fact, important for the ecosystem. But there is something else about them as intriguing as their role in the ecosystem- the way they fly. With their long and thin wings that are too weak to lift their weight, scientists have been baffled for long about how mosquitoes actually fly! The sweep of their wings covers a shallow angle of only 44 degrees, much smaller than that of any other insects. The short angle means that they need to flap their wings about 800 times per second, four times faster than any similarly sized insect - like a honeybee or a fruit fly, and hence, expend more energy. These characteristics of mosquito flight are unique to them.
Dr. Richard J. Bomfhrey, a scientist at the Royal Veterinary College, United Kingdom, and his team, in a recent study, explored on mosquito flight using high-speed cameras and computer models. They found that mosquitoes fly using three aerodynamic mechanisms - leading edge vortices, trailing edge vortices and rotational drag. When they flap down, small whirlwinds or leading edge vortices form at the front of their wings. On reversing this stroke, more whirlwinds or the trailing-edge vortices are formed at the back of their wings by using energy from the wake created by the previous leading-edge vortices. They also rotate their wings at the end to make use of the rotational drag for generating much of the lift required for flight. Only mosquitoes have been noted to use the last two mechanisms as well, instead of relying solely on leading edge vortices to stay aloft like other insects.
Finally you know what keeps them buzzing all the time. Now, scientists are questioning the evolutionary purpose of such a flight mechanism, given it is not very energy efficient. Who knew such obnoxious and ubiquitous mosquitoes could have something fascinating about them?