A group of researchers has seen fit to analyze the brain of female mosquitoes (only the latter feed on blood) when they choose their victim to suck the blood. Scientists at the University of Washington have discovered that mosquitoes use both the visual and olfactory systems to identify and track potential victims.
The mosquito chooses its victim by detecting some chemical signals and this had already been discovered previously. However, the ways in which these signals are processed in the brain and lead to the final decision were not known, at least until the study published today in Current Biology. First, the olfactory system detects the chemical signals of carbon dioxide coming from the potential victim and this causes changes in the brain of the mosquitoes. The intercepted carbon dioxide is essentially what we breathe out, an emission that mosquitoes can intercept even from a distance of more than 30 meters to locate the victim’s position and approach it.
After this first phase, the mosquitoes change their behavior and begin to use the visual system. With the latter they scrutinize the surroundings to delineate the forms of the guest and to decide to fly towards them. The researchers measured how carbon dioxide triggers these processes in the brain and modifies the flight behavior of mosquitoes.
With special equipment including an optical sensor to collect data related to the flapping of insect wings, the researchers have in fact tested the behavioral modalities of Aedes aegypti mosquitoes when they have to choose the victim. They discovered that even a small puff of air containing 5% of carbon dioxide could push a mosquito to turn towards the victim to visually locate it.