Bright light lessens the night bites
Although mosquitoes certainly do go after people during daylight hours, they're most active once the sun goes down. Therefore, if an "artificial sun" were to then come up – even briefly – would that cause them to bite less throughout the night? According to scientists at the University of Notre Dame, the answer is Yes.
Led by Prof. Giles Duffield, the researchers studied Anopheles gambiae mosquitoes, which are the major vector for transmission of malaria in Africa.
In the lab, control groups of the mosquitoes were left in darkened enclosures for the entire night, while other groups were exposed to bright white light for a period of 10 minutes at the start of the night, and then left in the dark.
For the rest of the 12-hour night, at two-hour intervals, the scientists regularly checked all of the groups' propensity to bite volunteers' arms. Even four hours into the night, it was found that the light-exposed groups bit significantly less than the control groups.
In another version of the experiment, in which the mosquitoes were subjected to the light sessions once every two hours, biting could be suppressed for most of the night. If the light was simply left on all night, though, it is believed that the mosquitoes would eventually adapt to it.
It is now hoped that the findings could be applied to the homes of African villagers, or other people at risk from mosquito-borne diseases. Of course, having a bright white light coming on every couple of hours could certainly be disruptive to those peoples' sleep. For that reason, the scientists are exploring the effectiveness of other less-jarring wavelengths of light, such as red light.
A paper on the research was recently published in the journal Parasites and Vectors.
Source: University of Notre Dame