The brain of mosquito mixes both smell and taste of the host to create an unusual and preferred flavor, reports a recent study conducted by researchers from Johns Hopkins University School of Medicine.
Developing a substance capable of making mosquitoes detest "human flavor" would help in protecting about 450,000 lives affected by the malarial parasite across the world every year, suggests the researchers.
According to the study published in the journal Nature Communications, on Oct. 3, all mosquitoes including Anopheles gambiae that spreads malaria find the suitable host with the help of their sense of smell. Christopher Potter, Ph.D., from Johns Hopkins said that the research is aimed at using mosquitoes to study the flavors repulsive to the insect to stay away from humans.
Mosquitoes have three pairs of so-called "noses" that includes two maxillary palps, two antennae and two labella. Thick and fuzzy maxillary palps protrude from lower portion of the head of the mosquito just parallel to proboscis. The proboscis is a flexible sheath that hides the "feeding needle" and the labella is found at the tip of the proboscis. Labella have two areas that contain gustatory and olfactory neurons for recognizing the tastes and odors respectively.
In order to find where the olfactory neurons end up in brain, Potter and team used an advanced genetic technique that will make the neurons glow "green" in color. Only the neurons that receive the odorant receptors would be labeled green in color.
As a result, it was observed that olfactory neurons from maxillary palps and antennae reached the antennal lobes similar to flies while olfactory neurons from the labella ended up in subesophageal zone. As a matter of fact, the subesophageal zone is not linked to sense of smell in any insect studied by far but was linked to sense of taste.
Potter noted that the study findings have it that the mosquitoes not only like the smell of humans but also the taste. The odorants taken up by labella could be influencing the mosquitoes' taste while trying to bite humans. The maxillary palps and antennae could be recognizing the long-range signals and the labella could be taking up the odor when in contact with the host.
"This suggests that a combination of repellants could keep mosquitoes from biting us in two ways," said Potter. "One could target the antennal neurons and reduce the likelihood that they come too close, while another could target the labellar neurons and make the mosquitoes turn away in disgust."
Potter, who said that his team would like to do further research on the topic, noted that this method could help in the development of a safe and good-smelling mosquito repellent.