Are there really fewer tiger mosquitoes at the moment in Toulouse? A specialist answers

In the space of a few years, its presence has become a real nuisance In Toulouse.

The tiger mosquito, present since 2012 in Toulouse

Detected for the first time in 2012, the tiger mosquito continues to establish itself in the Pink City, a metropolis that the small insect (around 5 mm) with black and white stripes has completely colonized in 2014.

And for several years, its presence (effective from May to November) has particularly increased to the point that it sometimes became difficult for the inhabitants of Toulouse to enjoy their exteriors (balcony, terrace or garden) certain summers.

However, at the start of summer 2024, the presence of this mosquito – which let us remember is daytime (it is capable of stinging as long as there is light, so it is not he who stings you during the night!) seems less strong than before. False impression or real trend In Toulouse ?

Where did the tiger mosquito go?

Toulouse News therefore contacted Guillaume Lacour, medical entomologist at Altopictus, company specializing in monitoring and combating the tiger mosquito.

And the scientist first makes the following observation: “The dynamics of abundance of tiger mosquito was comparable in spring 2024 with spring 2023: eggs hatching from March, first clutches at the end of April, etc.,” he indicates.

Half as many eggs in nest traps!

But the specialist notes a clear decline in the presence of the mosquito in the Deep South, and including in Toulouse, since June 2024, compared to the same month of the previous year.

“However, the abundance of the year 2024 has so far been lower than that of 2023 since the beginning of June, with on average 2.5 fewer Aedes albopictus eggs in the nesting traps of our scientific networks deployed in Occitanie and New Aquitaine”, indicates Guillaume Lacour at Toulouse News.

Altopictus in fact has a monitoring network about fifty nesting traps which are placed mainly around health establishments and a reinforced network around Toulouse-Blagnac airport. But last year, for the same period, the same specialist indicated to Toulouse news: “In June 2023, on our networks of nesting traps dedicated to monitoring, we observed an abundance of Aedes albopictus eggs tripled in the Toulouse metropolitan area, compared to June 2022, with variability depending on location.”

So how can we explain that there are fewer mosquitoes overall compared to last year at the same time?

How to explain this phenomenon ?

For the scientist from Altopictus, a company which deals in particular with mosquito control operations in Haute-Garonne in the event of the appearance of a case (imported or indigenous) of dengue, chikungunya or zika, it is obviously weather – unforgiving (to say the least!) – which is largely to blame.

” This decrease in abundance is most likely the consequence of much milder temperatures in May-June 2024 compared to May-June 2023 (e.g. -3.5°C in June 2024 in Toulouse compared to June 2023), temperatures which are finally approaching normal seasonal in 2024,” underlines Guillaume Lacour.

Residents also have a role to play

However, “lower temperatures lengthen duration of larval development (and therefore the risk of larval mortality if the water container is dried up in the meantime, for example),” adds the specialist.

Who further adds for the inhabitants of Toulouse and the region: “It is a good reminder that we must prevent the larval development of the tiger mosquito at home, by emptying every week water containers. Set yourself a tiger mosquito day, where you reflexively inspect your garden, terrace or balcony for 5 minutes: plant pots, gutter manholes, water storage containers, cups, etc. »

One of the most invasive species in the world

Because the Altopictus company recalls that the tiger mosquito “is one of the species the most invasive in the worldwhich is partly due to its great capacity for adaptation, and to the fact of having become “attached” to Man, which has enabled its regional and global dispersal, and which offers it shelter (the larvae of the tiger mosquito develop in the artificial containers that we accumulate: buckets, plant pots, vases, tires, sand traps, etc.) and cover (this mosquito preferentially bites mammals, including humans).

The best way to arm yourself against mosquitoes is to get rid of these famous containers which encourage the development of larval breeding sites…

“In no way a harbinger of a quiet summer”

But be careful… If the mosquitoes are therefore a little less present At the moment, this does not necessarily mean that the inhabitants of Toulouse and the surrounding areas will be able to relax on their balconies this summer! Everything will therefore depend on everyone’s individual actions… but also largely on the weather!

“As soon as temperatures rise, there will inevitably be more mosquitoes. It is therefore more of an episode of respite… But it is not in no way a harbinger of a quiet summer in Toulouse,” underlines Guillaume Lacour.

The abundance of mosquitoes will also depend on the precipitation that will occur this summer: “if it rains a lot, this will also favor their development and their presence over time”.

We will therefore have to wait a little longer to find out how the mosquitoes will… bite us!

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