Scientists from the California Institute of Technology and the University of Washington have conducted a study in which they showed how mosquitoes manage to attack humans. According to the study published in the journal Current Biology mosquitoes use their sense of smell in order to detect what species their next host is.
Besides their very accurate sense of smell mosquitoes have a whole strategy which also involves body heat, visual cues and odors. The insects have evolved and are able to use a triple threat of thermal, olfactory and visual cues. So citronella candles and bug repellents may work for a while, but they won’t keep the mosquitoes away forever.
According to Jeff Riffell from the University of Washington who is a co-author of the study researchers did not know much how mosquitoes choose their hosts and what the hosts look like for the insects. Previous research has only suggested that the mosquitoes’ sense of smell activates other senses as well when it comes to attacking the host.
Mosquitoes have come to be studied extensively because they can spread multiple diseases. They are responsible for spreading for example West Nile virus cases, malaria and yellow fever. That’s why it is important to study their behavior in order to find a way to stop their reproduction.
Mosquitoes and other insects in general are attracted by the carbon dioxide (CO2) which both humans and animals exhale. Besides this mosquitoes use their vision to identify the host and thermal sensory data to detect body heat.
In order to observe how the insects use each type of sensory data investigators used hungry, mated female mosquitoes which they released into a wind tunnel where the various sensory cues could be controlled independently. First the researchers tried to mimic human breath and they injected plume with a high concentration of CO2, whereas in a control experiment they used a low concentration of CO2. 20 mosquitoes were used in both cases. In order to follow the insects researchers used 3D tracking software and video cameras.
The findings of the study indicate that mosquitoes can smell a host’s CO2 plume from ten to 50 meters away and it can see it from five to 15 meter away. Afterwards with the help of visual cues mosquitoes can fell the body heat of the host from less than a meter.
The research team concluded that the study could be very helpful for medical experts who are trying to fight disease-spreading mosquitoes.
Image Source: expertbeacon.com