Light pollution may increase biting behavior at night in Aedes aegypti mosquitoes

Date:
October 20, 2020
Source:
University of Notre Dame
Summary:
Artificial light abnormally increases mosquito biting behavior at
night in a species that typically prefers to bite people during
the day, according to new research.



FULL STORY ========================================================================== Artificial light abnormally increases mosquito biting behavior at night in
a species that typically prefers to bite people during the day, according
to research from the University of Notre Dame that was published in The American Journal of Tropical Medicine and Hygiene.


========================================================================== Increased biting by Aedes aegypti mosquitoes, which normally fly and bite
in the early morning and during the afternoon, highlights the concern
that increasing levels of light pollution could impact transmission of
diseases such as dengue fever, yellow fever, chikungunya and Zika.

"This is potentially a very valid problem that shouldn't be overlooked,"
said Giles Duffield, associate professor in the Department of Biological Sciences, who is 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 in the vicinity of houses, so the chances of Aedes
aegypti being exposed to light pollution are very likely," he added.

To conduct the experiment, the study's first author, Samuel S. C. Rund,
a staff scientist in the Department of Biological Sciences, allowed
mosquitoes in cages to bite his arms under controlled conditions,
including during the day, at night or at night while exposed to
artificial light. The female mosquitoes - - the only ones that bite --
were twice as likely to bite, or blood-feed, at night when they were
exposed to artificial light. Twenty-nine percent of the mosquitoes in
the control group, which had no light, fed at night, while 59 percent
of the mosquitoes exposed to artificial light blood-fed.

The findings will help epidemiologists better understand the true risk
of disease transmission by this species. The discovery could also lead
to more recommendations for bed net use. Usually mosquito bed nets are
used at night to ward off bites from a different genus of mosquitoes, Anopheles, but because Aedes aegypti were shown to be stimulated by
artificial light, mosquito nets could also be used in areas with a
likelihood of disease transmission even with limited Anopheles activity.

"The impact of this research could be huge, and it probably has been overlooked," Duffield said. "Epidemiologists may want to take light
pollution into account when predicting infection rates." Duffield and his collaborators plan to experiment with additional variables of artificial
light to further study Aedes aegypti biting activity. These variables
include the duration of light, its intensity and color, and the timing
of the biting -- whether early at night or later. The team is also
interested in the molecular genetic pathways that might be involved with
biting activity, after noticing that not every mosquito in the population
under study was interested in biting at night even with artificial light.

"So, we think there is a genetic component within the Aedes aegypti
species," Duffield said.


========================================================================== Story Source: Materials provided by University_of_Notre_Dame. Original
written by Deanna McCool. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Samuel S. C. Rund, Laura F. Labb, Owen M. Benefiel, Giles
E. Duffield.

Artificial Light at Night Increases Aedes aegypti Mosquito Biting
Behavior with Implications for Arboviral Disease Transmission. The
American Journal of Tropical Medicine and Hygiene, 2020; DOI:
10.4269/ ajtmh.20-0885 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201020161202.htm

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