The biting season of mosquitoes that spread harmful West Nile virus and other pathogens can reportedly be extended due to urban light pollution, which is only growing by the day.
A study conducted by the Ohio State University has found that the phenomenon poses a robust threat to public health as mosquitoes can’t enter their winter dormancy period, or diapause, which means they can go about biting humans and animals for a prolonged period, according to Earth.com.
However, the study noted that aside from the negatives, the occurrence has some positive outcomes too.
Impacts of urban light pollution on mosquitoes’ extended biting season
Urban light pollution refers to a situation when over-the-top use of outdoor light can affect human health, and wildlife behavior, as well as interfere with the ecological balance.
Due to the added warmth emanating from the artificial lights, mosquitoes fail to enter their diapause period and accumulate sufficient fat reserves, which means they can’t survive the winter.
While this obviously is a piece of good news, researchers caution that the mosquitoes may remain active and biting well into the fall, leaving the disease caseloads peaking.
“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,” explained the study senior author Megan Meuti, Earth.com reported.
While the study is the first attempt to measure the impact of artificial lighting on mosquito behavior, any definitive conclusion was hard to arrive at, as the lights have varying impacts on the pests depending on seasons.
“We’re finding that the same urban light at night can have very different effects under different seasonal contexts,” she said, according to News-Medical.
Diapause is more of dormancy for female Northern house mosquitoes (Culex pipiens) than a winter slumber. During this phase, the pests use caves, culverts, sheds, and other semi-protected locations as hideouts and convert plant-nectar into fat for survival.
As days get longer, female mosquitoes go hunting for blood to enable egg production, and, most of them, who feed on infected birds, end up contracting the West Nile virus, which they then pass onto humans, horses, and other mammals.
The recent study gave an abundance of evidence that light pollution amounts to increased activity of mosquitoes and their low acquisition of nutrient reserves needed for fattening up and weathering winter temperatures.
“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,” said Matthew Wolkoff Ph.D. candidate in entomology at Ohio State and author of the study in a statement.
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