Views: 0 Author: Site Editor Publish Time: 2026-06-17 Origin: Site
Every autumn, the main vector of West Nile virus transmission in the United States, Culex mosquitoes, enters hibernation with gradually decreasing sunlight. However, a new study has found that even backyard lights are enough to delay these mosquitoes from falling asleep, thereby increasing their chances of biting people.
A recent study published in the Journal of Insect Physiology suggests that artificial light at night can severely disrupt mosquitoes' ability to enter a dormant state, and as cities become brighter, the season for disease transmission may also be extended. This study is very persuasive, "said Dina Fonseca from Rutgers University in the United States.
When autumn arrives, mosquito larvae hatch into adults, actively storing energy and preparing to spend the winter in cool, dark places such as basements and caves. Scientists have long known that shortened daylight hours are the main signal for mosquitoes to enter a dormant state, also known as "diapause".
Early laboratory studies have shown that low-intensity artificial light may interfere with mosquitoes and delay diapause. So, would the same situation occur in more complex urban environments?
To find the answer, researchers placed small containers for raising larvae in residential yards in Columbus, Ohio, some directly under existing outdoor lights, while others were hidden in natural dark corners of the same yard. After the larvae developed into adults, researchers collected these containers to test whether the mosquitoes inside had entered diapause or were still in an active period for feeding and reproduction.
Research shows that in September, the proportion of mosquitoes raised under light entering diapause is about 1/4 of mosquitoes in dark environments. In October, the comparison became even more apparent: every mosquito in the dark environment entered a diapause state, while 59% of mosquitoes exposed to light remained active.
The main author of the paper, Lydia Fyie from the University of Maine in the United States, said, "Light pollution has a much stronger inhibitory effect on overwintering dormancy than temperature. Even a light of only 0.87 lux (roughly equivalent to the night brightness under starlight) is enough to trigger mosquito activity.
If mosquitoes are active for a longer period of time, it means they will have more opportunities to infect and spread diseases. This also means that more mosquitoes may breed before winter arrives, leading to more mosquitoes appearing in the following spring and forming larger populations throughout the summer.
But Fonseca pointed out a key limitation of the study, which is that it did not use mosquitoes captured in the wild, but instead conducted research on laboratory cultured populations of Culex mosquitoes, which may have different responses when reproduced multiple generations under artificial conditions. However, she admitted that wild mosquitoes are very uncooperative in artificial environments, which makes any research on them in the laboratory extremely difficult.
The researchers stated that the next step will be to conduct long-term seasonal monitoring of wild mosquito populations in high and low light environments, tracking the multi-year changes in their diapause status starting and ending.
More and more evidence suggests that nighttime light has a significant impact on the biological characteristics and behavior of mosquitoes, "said Katie Westby from Washington University in St. Louis, USA." It is still an unanswered question how many mosquitoes extend their active period and what this means for their overwintering.
