Insect of cities, who arrived from the South, which moves thanks to the cars … visualize how the tiger mosquito colonizes France hexagonal

It measures a few millimeters, but its threat is growing. Consequently, The tiger mosquito extends its presence year after year through France. Furthermore, to the point of having now been identified in 81 of the 96 departments of France and Corsica, according to the government data updated in July. In addition, A real public health challenge: this distribution exposes the country to a risk of dengue. However, chikungunya and zika virus epidemic, so -called arboviroses diseases that are transmitted by “blood sucking” insects.

But how much is the tiger mosquito already present on our territory? Therefore, To understand the magnitude of this invasion. Moreover, Franceinfo has mapped the list of 6 608 municipalities of insect cities, who arrived south, France and so-called “colonized” Corsica, that is to say in which the tiger mosquito is considered to be installed. For example, These data. Therefore, which stop at 2024, were produced by the National Health Safety Agency (ANSES), which centralizes the identification made from citizen reports and laying traps.

Twenty years after its first colonization. identified in Menton (Alpes-Maritimes) in 2004, the insect is now installed in almost all of the southern part of France. “We can estimate that the tiger mosquito has completely invaded the southern third of the country”says Frédéric Simard. entomologist at the Institute of Research for Development.

The fact that some rare areas of the South is spared is explained either by an absence of reporting. or by conditions less conducive to the installation insect cities, who arrived south, of the parasite, as is the case in the mountainous territories of the Pyrenees or the Alps. “Municipalities at altitude constitute a less favorable environment. with lower temperatures”recalls Grégory L’Ambert, entomologist within the interdepartmental agreement for the demospecting of the Mediterranean coast.

From now on. it is towards the north that the Tiger mosquito extends its influence, starting with the big cities – its favorite playground -, in which it benefits from the proximity between the dwellings. Because the tiger mosquito has the distinction of not being the most skillful in the air.

“It is very small. Where larger mosquitoes can move for several kilometers, it has a radius of action only 150 meters.”

Frédéric Simard. entomologist at the Institute of Research for Development

in franceinfo

This handicap makes its progress slower in rural areas. The case of Creuse is emblematic of this insect cities, who arrived south, phenomenon. This department. one of the less densely populated in France, is the only one in the New Aquitaine region to be still preserved from the Tiger mosquito. “But there is no reason why he does not end up implanting it. It will just take more time”warns Frédéric Simard. Because if it only moves over small distances by itself, the tiger mosquito still manages to travel … thanks to man.

The insect benefits in particular from our cars. as researchers demonstrated in 2017, as part of a study carried out at the exit of a highway in northern Spain. The authors concluded that the parasite is potentially distributed by five cars out of 1. 000, during the summer, along the main roads in southern Europe. In France, the invasion of the tiger mosquito follows almost identically the route of the road network. “This is very visible on the axis of insect cities, who arrived south, the Highway of the Sun. between Marseille and Lyon”underlines Anna-Bella Failloux, entomologist at the Institut Pasteur.

In addition to entering cars, the Tiger Mosquito travels thanks to its eggs, which can withstand the lack of water for several weeks. It is in this form that this insect, from Southeast Asia, invaded the world from the 1980s. “Globalization has favored its spread. It arrived in the United States in 1985 and. from there, it developed on all inhabited continents, thanks to the tire trade, in which it had laid eggs”says Frédéric Simard.

It was insect cities, who arrived south, also through this that he had made his first appearance in France in 1999. “It had been found in a tire deposit located in the Orne department”specifies Anna-Bella failloux. But the insect had not settled in this Norman department. “Climatic conditions in the north of France are less conducive to the installation of the tiger mosquito”explains the researcher. He prefers “The alternation between hot and rain, with temperatures between 25 ° C and 32 ° C”she adds.

Among the 15 departments still spared in 2024, 14 are thus located in the northern part of the country. But this exception should not last. in a context of global warming which increases the periods conducive to the development of mosquitoes. “Ultimately, all the municipalities will pass by”says Frédéric Simard. He warns: “In ten years, it can be estimated that 90% of the French population will be exposed”.