In a new finding, researchers have revealed that mosquitoes have developed a triple threat of visual, olfactory and thermal cues to locate humans and then bite them. With the help of their remarkable smelling ability, mosquitoes locate hot-blooded bodies and then they use their other senses including vision to suck the blood of the target, said researchers from the University of Washington and the California Institute of Technology,
While explaining the bite procedure, researchers said — Mosquitoes can smell host’s carbon dioxide (CO2) plume from 10 to 50 meters away. Then the mosquito flies towards the host and at a distance of 5 to 15 metres it starts seeing the host. Then with the help of its vision it moves closer to the host’s body and when it is nearly 1 metre away it starts feeling the body heat of the host. At last the mosquito chooses the bite location and eventually decides to leave its mark.
To demonstrate it, researchers released hungry, mated female mosquitoes into a wind tunnel under controlled condition. To mimic the human breath, scientists injected high-concentration CO2 plume into the tunnel. In a different set, researchers also introduced a plume consisting of background air with a low concentration of CO2. The study authors found that the mosquitoes followed concentrated CO2 plumes in the tunnel, but they showed no interest in a control plume consisting of background air. The research team also introduced dark object in the presence of CO2 plume and found that the mosquitoes were attracted towards the object, but in the absence of the CO2 plume they showed no interest in it.
It was also found that mosquitoes were attracted more towards warm objects. However, visual attraction towards objects was not dependent on the presence of CO2 plumes. The study has given new insight into the behaviour of mosquitoes. Until now very little was known about how a mosquito chooses its landing location ans then starts feeding without getting into notice.
Among all animals and insects, mosquitoes kill most number of people with nearly one million death every year. The study will help scientists to design better mosquito repellants and traps in near future so that mosquito bite can be prevented, hence several deaths.
The study appeared in the journal Science Direct.