“Now is the time to deprive the tiger mosquito of water”: a mosquitoologist explains how to prevent the proliferation of the insect

The tiger mosquito returns ? Free Midi – SCANNER

The first larvae of the Aedes albopictus were observed in Occitania thanks to the rains and spring heat. Mosquitoologist Anna-Bella Failloux recalls the good practices to protect yourself from an insect that appeared 20 years ago in France and which, this year, ended up colonizing the entire country.

Can we say that in 2024 the tiger mosquito has colonized the whole of France ?

Of the 13 French regions, only Normandy remained, and during surveys carried out in 2023, it was found in Seine-Maritime so yes, we can say that it is everywhere in France. And its playing area will, due to climate change, move more and more towards the north of Europe. It’s only a matter of time because once this mosquito is established, it stays for a long time. It’s linked to its biology. Female eggs can withstand periods of drought lasting weeks, months, or even years as well as the low temperatures of winter. They wait for the spring rains then when the climate warms up with a photoperiod that lengthens… As soon as all conditions are met, it comes out after a period of break.

Yet it arrives from Asia, how is it that they have adapted to our climate?

It’is an invasive species that adapts and circulates between continents through the exchange of goods. It was introduced by human activities. It left Asia and settled in the United States via retreaded tires in small quantities of water where the eggs give rise to larvae then adult mosquitoes. It then arrived in the port of Genoa in 1990 and invaded all of Italy then crossed the border into France in 2004. 20 years later, it is now everywhere.

Anna-Bella Failloux, is a professor of entomology and mosquitoologist. FREE NOON – T.R.

Are there places where he feels less comfortable?

Where it is very hot like the Sahel or very cold like in the far North, but this changes with global warming like in Canada where, during two summer months we can have tiger mosquito because it's quite hot.

However, it is not just a pest, it is above all a vector of diseases ?

If he only bothered us at aperitif time it wouldn't be annoying but in fact, he transmits viruses like dengue, chikungunya and zika which are diseases infectious. By biting people who arrive in France and who are carriers of this virus. Because there is no such thing as a wild cycle. The virus always comes from travelers. But by biting, during the hot period, will transport and multiply in the body of the mosquito and by biting again will transmit the virus. This becomes an indigenous case and the number has increased from one or two cases to around forty in 2023 and we will see in 2024, with the Olympic Games in Paris, and the concentration of people from all over the planet, this could be much more. Especially since in these diseases, there are many asymptomatic cases.

Why do we say the tiger mosquito is an urban mosquito ? 

Because it is found in cities, far from the coast, colonizing containers of relatively clean water, unlike the culex which likes water laden with organic matter. Small shelters, very small quantities are enough. Even in a cap with water inside is enough. You have to deprive it of water, hunt down the smallest container so as not to have a tiger mosquito. But for it to work, you and your neighbor have to do it. If he doesn't do it, there's no point. The entire population must address this problem. If we want to have a peaceful summer, now is the time to deprive it of water, because without water it cannot live.

Can we fight other than by depriving him of water?

If you have to use chemicals, it’s very complicated because most of them are resistant to the products used. The mosquito adapts, survives and transmits from generation to generation, the memory of this resistance… hellip; There are few insecticide molecules, only one is used against adults, it is deltamethrin and we must be careful with its use not to increase the doses to deal with the resistance of the insect. ;insect. This has consequences on everything that is not targeted: birds, other insects… hellip; this generates chemical pollution.

“Very expensive” control techniques

New techniques have appeared in recent years to combat the tiger mosquito. Anna-Bella Failloux judges two of them. The first, the so-called sterile mosquito technique, which consists of sterilizing male mosquitoes by UV radiation or gamma rays and releasing them in large quantities into the wild so that mating with the female does not occur. no eggs, the mosquitoologist estimates it "extremely expensive. You need a male mosquito factory, sort them in the nymph state, irradiate them, release them into the wild and make them competitive. Often, it is not in good shape and it arrives after mating with a wild insect, but the female mosquito has the capacity to retain large quantities of sperm" .

As for the trapping technique which consists of mimicking human odors, "this works well in a closed room, less so in nature, because the smells will compete". Here too the system can turn out to be very expensive and particularly energy consuming: "You might as well have mosquito nets or at least find the right compromise, compatible with the environment. "

Is it illusory to consider that it can be eradicated ?

Clearly yes. The first insects appeared on earth 400 million years ago, mosquitoes appeared 240 million years ago, well before the first mammals. They took blood from the first reptiles including dinosaurs. They existed long before Man and will probably exist long after.

In France we complain about it especially for the nuisances during the summer?

There are 77 species of mosquitoes in France, compared to 300 in Guyanne. While in countries less wealthy than France, diseases transmitted by mosquitoes kill: malaria, it’s 500,000 deaths on the planet, dengue 50,000… In France, you can be sick, but there are almost no victims.

And natural techniques?

This may work occasionally. But why will a female bite you?? Because of the bacteria you have on your skin and which depends on what state you are in. Depending on whether you ate spicy, whether you sweated, which depends on your genetics… And even sometimes you become insensitive because you develop resistance. It’s very complex and I’ll say it again, you have to get used to living with it and deprive it of water!

In 1974, a discreet arrival in Albania

Proof that it is commercial exchanges which allow the tiger mosquito to proliferate, Anna-Bella Failloux recalls that "the first time that we have trace of a tiger mosquito in Europe, it" It was in 1979. He arrived from China but remained confined to the country because the country was communist and had no exchange with the outside world with the exception of China".

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