We used to hear them sing, fly or buzz in our lands, but they have disappeared. In Ile-de-France, dozens of species of grasshoppers, butterflies and dragonflies are now considered extinct, according to the Regional Biodiversity Agency in Île-de-France (ARB îdF), which in February published the third of its “red lists” of threatened insect species. 20 minutes has chosen to present to you three of these little critters that have become invisible, in order to bring them to life, at the very least, in our memories.
The Azure of the Moullières
More than one in three species of butterflies in the region is currently threatened or has disappeared. Of the 135 species of butterflies recorded, 18 have completely disappeared. L’Azure of the wetness has not been seen in Ile-de-France since 1993. Its survival depends on a delicate balance between the presence of its host plant, the gentian, and that of an ant, the Myrmica scabrinodis, according to Hemminki Johan, in charge of studies at ARB. The caterpillars consume the flower and the ants are attracted by pheromones that the caterpillars release. The caterpillar of the Azuré des mouilleres mimics the behavior of ant larvae and even “goes so far as to emit stridulations similar to those produced by their queen”, explains Hemminki Johan. The goal: to be brought into the anthill and delight in the larvae of ants, while being pampered for months… According to the ARB research officer, the Azuré des mouillères “suffered from the drainage, the setting in cultivation and improvement of wet meadows. The mowing at the beginning of summer or the undergrowth of its habitat has also been detrimental to it”.
The Alpine Decticella
Did you know ? France has 220 species of grasshoppers, locusts and other crickets. Of the 63 species assessed in Ile-de-France by the ARB îdF, 14 are threatened. And four are considered “regionally extinct” outright, species that have “historically shown evidence of breeding in the region and have not been observed regionally since 1997.” Among these are the Mountain Decticella, formerly present in the wood of Notre-Dame, located astride the Val-de-Marne and the Seine-et-Marne. It is a small grasshopper that lives mainly in mountainous areas, such as the Alps, the Pyrenees, the Jura and the Vosges. She deserted the forest of Notre-Dame because of “the undergrowth of the meadows, their drying out and global warming”, explains to 20 minutes Hemminki Johan. “This species is increasingly pushed back to altitude where it still finds biotopes and climatic conditions favorable to its development,” adds the scientist.
The Orange Agrion
Of 58 species of dragonflies observed in Île-de-France, one is considered “regionally extinct”, the orange agrion. It is a species that likes slow running waters and ponds with wooded banks. We had no news of this butterfly in Ile-de-France since the beginning of the 1990s, around the Fontainebleau massif. “But in 2021 data was observed near Etampes, which clearly shows that the red lists must be updated and that there is sometimes good news”, explains Hemminki Johan, who thinks that “climate change will have an effect favorable on this species and that it is possible that it will be more present in the future in the region”.
According to the ARB, in Île-de-France, the degradation of natural areas is one of the main reasons for the decline of insect populations, and pollution also causes them serious damage.