Light pollution could be making mosquito season longer

By Jim Leffman via SWNS

Light pollution could be making mosquitos bite us for longer, a new study from Ohio State University found.

Researchers say night light disrupts the insects' winter dormancy period making them continue to be active further into the fall and early winter.

They believe that light prevents them from fattening up prior to shutting down over the colder months.

They are not sure whether this is good news as they could not then survive winter or bad news, that they just carry on biting longer to store up enough fat.

The problem was studied by Ohio State University, where West Nile Virus is particularly prevalent to spread in late summer and early autumn.

The virus causes headaches, body aches, joint pains, vomiting, diarrhea, or a rash. In some cases, the fatigue and weakness can last for weeks or months.

The winter break, known as the diapause is a period of dormancy when the insects live in caves, culverts, sheds and other semi-protected locations.

Prior to winter’s arrival, mosquitoes convert sugary sources, such as plant nectar, into fat.

Some get infected with West Nile virus by feeding on infected birds, and later transmit the virus when they feed on people, horses and other mammals.

A doctoral student at Ohio, Lydia Fyie, found that female mosquitoes exposed to light at night postponed diapause and became reproductively active, foraging for blood meals to enable egg production.

Exposure to light pollution suppressed the number of water-soluble carbohydrates, sugars that are an essential food source during winter, that were accumulated by mosquitoes.

Senior author of the study and an assistant professor of entomology at The Ohio State University, Megan Meuti said: "We see the highest levels of West Nile virus transmission in the late summer and early fall in Ohio.

"If you have mosquitoes postponing or delaying diapause and continuing to be active longer in the year, that’s at a time when the mosquitoes are most likely to be infected with West Nile virus and people could be at greatest risk of contracting it."

But first author and doctoral student Matthew Wolkoff said that putting off diapause might not be good for the insects.

He said: "This could be bad for mammals in the short term because mosquitoes are potentially biting us later in the season, but it could also be bad for mosquitoes in the long term because they might be failing to fully engage in preparatory activities they need to survive the winter during diapause, and that might reduce their survival rate."

This study and earlier findings by Prof Meuti and her colleagues are among the first to show that artificial light at night could have a significant impact on mosquito behavior.

The research, published in the journal Insects, was carried out under lab conditions.

Prof Meuti added that more research needs to be done in the wild, saying: “We’re finding that the same urban light at night can have very different effects under different seasonal contexts."