Why is this insect, well known in the south of France, heard in Grenoble?

For the inhabitants of Grenoble and Isère, it was a sign that the Mediterranean Sea was approaching. The cicada has been present in the department for about 10 years. Specialists then only identified one species, but today the number of cicada species is estimated at nine.

An evolution that is not the result of chance but that of global warming. We tell you everything about the “wildlife drift” which is disrupting biodiversity in Grenoble.

What is “wildlife drift”?

Gilles Desrumeaux, biodiversity specialist testifies “to hear more and more cicadas” near his home, in the suburbs of Grenoble. Main cicada species present in Isère, the red cicada, measuring 45 mm, is recognizable by its continuous noise that can reach 90 decibels.

Plebeian and gray cicadas are now well established in the biodiversity of Isère. If their name will surely escape you at the end of the article, it is important to remember that the arrival of these new species is not trivial.

“We are facing a wildlife drift” warns Gilles Desrumaux before explaining the term used: “global warming causes certain species of animals to move further north”.

With regard to cicadas, the member of the Rosalia entomological club explains that “cicadas sing between 22°C and 25°C and need tall grass and soil”.

If the trees are surrounded by concrete, the cicadas cannot survive since they lay eggs in the trees and the larvae will then bury themselves in the ground. Gilles Desrumaux shares a funny anecdote with us: “Contrary to what one might think, there are no cicadas in Marseille because the city is very little vegetated.

How dangerous are cicadas?

The presence of these numerous cicadas in Grenoble and in the neighboring towns does not represent a danger. The natural predators of these insects are small birds of the tit or sparrow type, which makes it possible to regulate their number.

Gilles Desrumaux points to two issues raised by the presence of cicadas: “like many insects, they can weaken trees. The second inconvenience is for the local residents…but quite honestly, it’s nice to hear the cicadas”.

Species will disappear

Asked by News Grenoblethe insect specialist indicates that “global warming will be at the origin of departures and arrivals of certain species”.

In the next few years insects will go up north and others will disappear.

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