Artificial light abnormally increases mosquito bite behavior in a species that people normally prefer to bite during the daytime, according to research by the University of Notre Dame.
The increased biting of Aedes aegypti mosquitoes, which usually fly and bite in the early morning and afternoon, underscores concerns that increased light pollution could affect the transmission of diseases such as dengue, yellow fever, chikungunya and zika.
“This is possibly a very legitimate problem that shouldn’t be overlooked,” said Giles Duffield, Associate Professor in the Department of Biological Sciences, also affiliated with the Eck Institute for Global Health and the Neuroscience and Behavior Program. Unlike other species that may emerge from the forest to feed on humans and animals, Aedes aegypti evolved with humans and prefers to feed on them.
“They live and breed near houses, so Aedes aegypti is very likely to be exposed to light pollution,” he added.
To conduct the experiment, the study’s lead author, Samuel SC Rund, a member of the Department of Biological Sciences, allowed mosquitoes in cages to bite their arms under controlled conditions, including during the day, night, or night when exposed to man-made agents Light. The female mosquitoes – the only ones that bite – were twice as likely to bite or bleed at night when exposed to artificial light. 29 percent of the mosquitoes in the control group who had no light ate at night, while 59 percent of the mosquitoes were exposed to artificial light that was blood-fed.
The results will help epidemiologists better understand the true risk of disease transmission from this species. The discovery could also lead to further recommendations for the use of the bed net. Mosquito nets are usually used at night to repel bites from another genus of mosquitoes, Anopheles. However, since Aedes aegypti has been shown to be stimulated by artificial light, mosquito nets can also be used in areas where there is a likelihood of disease transmission and limited Anopheles activity.
“The implications of this research could be enormous, and it has likely been overlooked,” said Duffield. “Epidemiologists may want to consider light pollution when predicting infection rates.”
Duffield and his co-workers plan to experiment with additional artificial light variables to further investigate the biting activity of Aedes aegypti. These variables include the duration of the light, its intensity and color, and when it was bitten – whether early in the night or later. The team is also interested in the molecular genetic pathways that may be linked to biting activity after finding that not every mosquito in the population studied was interested in biting at night even in artificial light.
“So we believe that the Aedes aegypti species has a genetic component,” said Duffield.
Artificial light at night increases the mosquito bite behavior of Aedes aegypti with effects on the transmission of arbovirus diseases. The American Journal of Tropical Medicine and Hygiene, October 15, 2020.