Summer evenings by the pool, lake or barbecue are synonymous with mosquitoes. But what about in winter when we are mostly indoors? As the weather gets colder, these bloodsucking pests are rarely seen.
But where are they going?
Hot and humid conditions are suitable for mosquitoes
Mosquitoes have complex life cycles that depend on the water brought to wetlands, floodplains and water holding reservoirs by seasonal rainfall. According to whether we live a summer under the influence of El Nino Where the girlmosquito populations will change in different ways.
During the warmer months, their life cycle lasts about a month. Eggs laid around the water hatch and immature mosquitoes go through four stages of development. The larvae then pupate, from which an adult mosquito emerges, sits briefly on the surface of the water, then flies away to buzz and bite and continue the cycle.
Water is crucial, but temperature is very important too. Unlike warm-blooded animals, mosquitoes cannot control their own body temperature. The hotter it is, the more active the mosquitoes will be. There are usually more.
But once the cold comes, their activity slows down. They fly less, they bite less often, they reproduce less and their life cycle takes longer to complete.
Temperature also plays a role in determining the ability of mosquitoes to spread viruses.
Cold weather is not good for mosquitoes, but millions of years of evolution gave them a some tips to survive.
Mosquitoes do not disappear completely
On a sunny winter afternoon, you might notice the occasional mosquito buzzing around your garden. Not as much as in summer but they are still there.
Some mosquitoes disappear. For example, the activity of the harmful mosquito Culex annulirostrisconsidered to play an important role in the Japanese encephalitis virus spread in Australia, decreases significantly when temperatures begin to drop below 17.5℃.
Study in Sydney showed mosquitoes, such as Culex annulirostris, vanish. Others, like Culex quinquefasciatus and Culex molestus, remain active all winter. You may not notice them (unless they come into your house to buzz in your ears).
Mosquitoes can disappear in diapause
We know the idea that mammals hibernate during the winter, but mosquitoes, like many other insects, can enter a phase of inactivity called diapause.
Once cold weather arrives, adult mosquitoes find hiding places such as tree hollows and animal burrows, in the cracks and crevices of bush environments, or in garages, basements or garages. other structures around our homes, suburbs and cities. These mosquitoes can only live for a few weeks in summer, but entering diapause allows them to survive for several months in winter.
Mosquitoes can also be found in frozen bodies of water, whether it’s a bucket of water in your yard or an almost frozen wet area. For example, there is a group of mosquitoes belonging to the genus Coquillettidies whose larvae attach submerged parts of aquatic plants and can survive cold winter temperatures. Their development slows down considerably, and they will remain in the water until spring arrives.
All their eggs in a winter basket
Some mosquitoes survive the winter on their eggs. Mosquito eggs can be incredibly resilient. They survive drying out in hot, salty coastal wetlands during summer, but also frost in snowy creeks in winter.
In coastal regions of Australia, the eggs of the salt marsh mosquito (Aedes Vigilax), sit perfectly securely on the floor. Once the weather warms up and the tides bring water to the wetlands, these eggs will be ready to hatch.
There is also a special mosquito in Australia known as the “melting snow mosquito” (Aedes nivalis) whose the eggs survive under the snow and hatch once the snow melts and fills ponds, streams and wetlands throughout the alpine regions.
Does it matter where mosquitoes go in the winter?
It’s not just mosquitoes that survive the cold months. Viruses, such as Japanese encephalitis virus Where Ross River Viruscan survive from summer to summer in mosquito eggs, immature stages or diapausing adults.
Knowing the seasonal spread of mosquitoes helps health authorities design surveillance and control programs. It may help to understand how invasive mosquitoes survive conditions in Australia outside their native ranges by hide from the coldas in rainwater tanks.
Even mosquitoes commonly found in tropical regions can even adapt to cooler climates.
This knowledge may even reveal the cold crack in mosquito armor that we can use to better control mosquito populations and reduce the risk of outbreaks.
Cameron Webbclinical associate professor and senior hospital researcher, University of Sydney
This article is republished from The conversation under Creative Commons license. Read it original article.
#mosquitoes #winter