2023-08-30 17:09:00
A recent study by researchers at Ohio State University reveals that urban light pollution can have a significant impact on the winter dormancy period, or diapause, of mosquitoes and on the biting season of mosquitoes that transmit West Nile virus. western. This finding has both positive and negative implications for public health.
On a positive note, research suggests that if mosquitoes are unable to enter their diapause period and accumulate sufficient fat stores, they may not survive the winter. However, the negative side of the equation is that disruption of diapause might lead mosquitoes to remain active and bite humans and animals later in the fall.
Professor Megan Meuti, lead author of the study, explained the potential consequences of this disruption: “We see the highest levels of West Nile virus transmission in late summer and early fall. in Ohio. If mosquitoes delay or delay diapause and continue to be active longer in the year, this is a time when mosquitoes are most susceptible to West Nile virus infection and people run the greater risk of contracting it.
The study is among the first to demonstrate the potential effects of artificial light at night on mosquito behavior. Interestingly, the researchers found that the impact of urban light pollution on mosquitoes is not entirely predictable, as the same light sources can produce varying effects depending on the season.
How do you study mosquitoes
For the study, recently published in the journal InsectsMeuti collaborated with the study’s first author, Matthew Wolkoff and Lydia Fyie, both doctoral students in entomology at Ohio State,
The research focused on the diapause of female northern house mosquitoes (Culex pipiens), which is not complete winter sleep but rather a period of dormancy during which the insects reside in semi-protected places such as caves. , culverts and sheds. Before winter sets in, mosquitoes convert sweet substances like plant nectar into fat, which keeps them going through diapause.
As the days lengthen, the female mosquitoes begin to seek blood meals to enable egg production. Some of these mosquitoes become infected with West Nile virus following feeding on infected birds, then transmitting the virus to humans, horses, and other mammals during subsequent feedings.
The study builds on two previous findings from Meuti’s lab, including the finding that circadian clock genes differ between diapausing and non-diapausing mosquitoes, which strongly indicates that day length determines the onset of diapause. More recently, research by Fyie found that female mosquitoes exposed to low light at night avoided diapause and became active breeders, even when the shorter days suggested they should be dormant.
What causes mosquitoes to bite
In a recent study led by Wolkoff, researchers found that artificial light at night had a significant impact on mosquito behavior and nutrient buildup. The findings, which might have implications for both humans and mosquito populations, shed new light on the complex relationship between insects and their environment.
To explore this relationship, the research team studied mosquitoes in two different laboratory environments: one simulating long days, which corresponds to the insects’ active season, and another with short days, inducing a period of dormancy called diapause. In each condition, mosquitoes were exposed to artificial light at night.
The study found further evidence linking mosquito behavior to circadian patterns. During diapause, insect activity levels decreased, but their circadian rhythm remained constant. This finding suggests that even during periods of dormancy, mosquitoes maintain a predictable activity pattern.
However, the introduction of artificial light at night disrupted these patterns and influenced the ability of mosquitoes to build up stores of nutrients, essential for surviving winter temperatures. For example, exposure to light pollution reduced the amount of water-soluble carbohydrates – a vital food source in winter – accumulated by mosquitoes during long and short days.
Other factors that trigger mosquito bites
Additionally, the researchers found that exposure to artificial light at night altered the buildup of glycogen, a type of sugar. Under normal conditions, nondormant mosquitoes had elevated glycogen levels, while diapausing mosquitoes did not. But when subjected to light pollution, long-day mosquitoes accumulate less glycogen, and short-day mosquitoes have increased glycogen accumulation.
In terms of activity, the researchers observed consistent trends when the mosquitoes were exposed to artificial light at night. Dormant mosquitoes showed a slight increase in activity, while long-day mosquitoes showed slightly suppressed activity. Although these results are not statistically significant, Wolkoff believes that the combined observations suggest that light pollution may disrupt diapause in mosquitoes by interfering with their circadian clock signals.
“This might be bad for mammals in the short term, as mosquitoes might bite us later in the season, but it might also be bad for mosquitoes in the long term, as they might not fully engage in preparatory activities. they need to survive the season. winter during diapause, which might reduce their survival rate,” Wolkoff explained.
The findings highlight the need for further research to better understand the complex relationship between urban light pollution, mosquito behavior and West Nile virus transmission. Developing strategies to mitigate the potential risks associated with disrupted diapause might prove critical to protecting public health from the spread of mosquito-borne diseases like West Nile virus.
To confirm the validity of these laboratory results, the research team plans to conduct field studies to examine the effects of artificial light at night on mosquitoes in their natural environment. Such studies might provide valuable insight into the role of light pollution in altering mosquito behavior and survival, which might impact ecosystems and human health.
Other recent advances in the war on mosquitoes
Over the years, researchers have made significant progress in understanding the behavior, biology, and disease transmission of mosquitoes, which has led to the development of various innovative strategies to prevent the spread of mosquito-borne diseases. . Here are some notable advancements:
Genetic modification: Scientists have developed genetically modified mosquitoes that can either suppress the population or reduce their ability to transmit disease. For example, the release of genetically modified male mosquitoes carrying a self-limiting gene can give rise to offspring that will not survive to adulthood, ultimately leading to a decline in the mosquito population. Wolbachia Bacteria: The introduction of Wolbachia, a naturally occurring bacterium, into mosquito populations has shown promise in reducing disease transmission. Mosquitoes infected with Wolbachia have a reduced ability to transmit viruses such as dengue, Zika and chikungunya. The bacteria can be passed on to future generations, making it a sustainable approach to controlling the spread of the disease. Insecticide-treated nets: Long-lasting insecticidal (LLIN) nets are an effective method to prevent mosquito bites and reduce malaria transmission. These mosquito nets are treated with insecticides that repel or kill mosquitoes on contact, providing a physical and chemical barrier for people sleeping underneath. Spatial repellents: Researchers are developing spatial repellents, which can be used indoors or outdoors to create an area where mosquitoes are less likely to bite humans. These repellents typically contain chemicals that affect the olfactory or taste systems of mosquitoes, making it more difficult to locate human hosts. Larval source management: This approach involves targeting mosquito larvae and reducing their breeding sites. Methods include environmental management, such as eliminating sources of standing water or introducing predators that feed on mosquito larvae, and larviciding, which involves applying chemical or biological agents to kill mosquitoes. larvae. Vaccine development: Scientists are actively working to develop vaccines once morest mosquito-borne diseases, such as malaria and dengue fever. Although progress has been made, vaccine development remains a challenge due to the complex life cycles of these pathogens and their ability to evade the human immune system. Improved surveillance and early warning systems: Advances in technology have enabled better monitoring of mosquito populations and disease outbreaks, allowing for earlier interventions and more targeted control measures. This includes using satellite data, drones and machine learning algorithms to predict and track mosquito-borne disease outbreaks.
These advances, along with continued research and collaboration between scientists, policymakers and communities, might significantly reduce the impact of mosquito-borne diseases on global public health.
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