Nanoparticles prove effective against the yellow fever mosquito
Carbon black is fatal for its larvae in standing water

Date:
April 19, 2022
Source:
Ohio State University
Summary:
Before being accidentally introduced to the New World by the 16th
century slave trade, the yellow fever mosquito was a species native
only to Africa. Highly adaptable, it has since become an invasive
species in North America, but researchers at may have found a way
to squash the pesky population in its juvenile stages.



FULL STORY ========================================================================== Before being accidentally introduced to the New World by the 16th century
slave trade, the yellow fever mosquito was a species native only to
Africa. Highly adaptable, it has since become an invasive species in
North America, but researchers at The Ohio State University may have
found a way to squash the pesky population in its juvenile stages.


========================================================================== Recently published in the journal Insects, a new paper describes
how mosquitoes have evolved a natural resistance to some chemical
insecticides, and offers an alternative called carbon black, a type of carbon-based nanoparticles, or CNPs.

Study co-author and an associate professor of entomology at Ohio State,
Peter Piermarini described CNPs as "microscopic" materials made out of
organic elements. The study used a modified version of carbon black called Emperor 1800, which is often used to coat automobiles black. While CNPs
are a relatively new scientific development, they have been considered
as new tools to control various insect and pest infestations, he said.

"If we can learn more about how carbon black works and how to use it
safely, we could design a commercially available nanoparticle that is
highly effective against insecticide-resistant mosquitoes," Piermarini
said.

The yellow fever mosquito, or Aedes aegypti, is a species of mosquito
known for spreading not just yellow fever, but also diseases like the Zika virus, dengue fever and chikungunya fever. Adults rarely fly more than
a few hundred meters from where they emerge, but their abundance leads
to steady transmission of diseases -- enough to claim tens of thousands
of lives every year and hospitalize hundreds of thousands more people.

Because of this, the mosquito is considered to be one of the deadliest
animals on the planet. For this study, the researchers' goal was to
figure out how toxic these nanomaterials could be to mosquito larvae,
or the immature form of the insect.



========================================================================== Contrary to popular belief, not all mosquitoes set their sights on turning
our blood into their latest meal. Male mosquitoes subsist only on flower nectar; it's the females that will consume both flower nectar and blood
in a bid to provide their eggs with enough protein to grow.

When female mosquitoes are ready to lay their eggs, they return to
standing pools of water, like lakes or birdbaths, to release them. After
they hatch, these larvae will stay in the water for about a week until
they reach adulthood, and take wing.

To test whether Emperor 1800 would be effective in stopping that
process, researchers worked with two different strains of the yellow
fever mosquito inside the lab, one extremely susceptible to typical
chemical insecticides, and the other, extremely resistant to them.

By applying the carbon black nanomaterials to the water during the
earliest stages of the mosquito's life cycle and checking in 48 hours
later, they were able to determine that CNPs kill mosquito larvae both
quickly and efficiently.

"Given the properties of carbon black, it has the most potential
for killing larvae because it can be suspended in water," Piermarini
said. Their findings showed that the material seemed to accumulate on
the mosquito larvae's head, abdomen, and even in its gut, meaning that at
some point, the larvae were ingesting smaller particles of carbon black.



==========================================================================
"Our hypothesis is that these materials may be physically obstructing
their ability to perform basic biological functions. It could be blocking
their digestion, or might be interfering with their ability to breathe,"
said Piermarini.

However, there was one thing that Piermarini found particularly
surprising.

When first suspended in water, carbon black appeared equally toxic to
larvae of insecticide-resistant and insecticide-susceptible mosquitoes,
but the longer the carbon black was suspended in water before treating
them. it became more toxic to the insecticide-resistant larvae.

"When you first apply the CNP solution it has similar toxicity against
both strains," Piermarini said. "But when you let the suspension age for
a few weeks, it tends to become more potent against the resistant strain
of mosquitoes." Although they couldn't determine the reason behind the time-lapsed deaths, the study concluded that these new nanomaterials
could be extremely beneficial to controlling the species when applied
as a preventive treatment to mosquito breeding grounds.

But before it can be utilized by the public, Piermarini said, carbon
black needs to undergo rigorous testing to ensure it won't harm humans
and the environment as a whole.

Co-authors were Erick Martinez Rodriguez, a visiting scholar currently in
the Ohio State Entomology Graduate program, Parker Evans, a previous PhD student in the Ohio State Translational Plant Sciences Graduate program,
and Megha Kalsi, a previous postdoctoral researcher in entomology. This research was supported by Ohio State's College of Food, Agricultural,
and Environmental Sciences and Vaylenx LLC.


========================================================================== Story Source: Materials provided by Ohio_State_University. Original
written by Tatyana Woodall. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Erick J. Marti'nez Rodri'guez, Parker Evans, Megha Kalsi, Noah
Rosenblatt, Morgan Stanley, Peter M. Piermarini. Larvicidal
Activity of Carbon Black against the Yellow Fever Mosquito Aedes
aegypti. Insects, 2022; 13 (3): 307 DOI: 10.3390/insects13030307 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220419103236.htm

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