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05.05.2022 | Kommentarer

Invasive species : The Asian Hornet in France

The Asian hornet (Vespa velutina), has colonized France and is spreading in Europe, this species acclimatizes easily to new territories and reproduces very quickly, thus making numerous ravages to bees and other pollinating insects. We find this species in the north of India, in China and in the mountains of Indonesia; it usually lives in gardens and green spaces and feeds on social insects. The Asian hornet is mainly black, with a broad orange band on the abdomen and a yellow first segment. Its head is orange, seen from the front, and its legs are yellow at the ends. It measures between 17 and 32 mm. It is smaller than the European hornet.

It seems to have arrived in France hidden in a shipment of Chinese pottery delivered in 2004 to Tonneins (Lot-et-Garonne). In a few years, it has proliferated all over France and has also spread to Spain and Portugal. Vespa velutina has spread to 24 regions from the Charente-Maritime to the Gard. Researchers have observed through genetic studies that samples taken from different nests had the same DNA sequence. So the hornets studied all have the same genetic characteristics; this means that a single mother would be the origin of all the Asian hornets present in France today. It took the arrival by chance of a single Asian hornet queen to spread this invasive species.

The proliferation of this species is very fast, indeed a nest gives four nest the year after. Moreover, there are not a lot of predators of the hornet in Europe, allowing them to cause significant harm by attacking bees. Bees constitute 80% of the hornets' diet. Nectar harvests and pollination are then strongly impacted. The hornet will cause the loss of many bee colonies by decreasing their activity but also by stressing them, leading many times to the death of these insects. The Asian hornet is therefore a major threat to European biodiversity, preventing the reproduction of many species of flowering plants due to the lack of bees. Hornets also cause damage in orchards by eating fruit, they recover the sugar present in the fruits causing them to rot. Leading to a decrease in the quality of the products in the wine sector. The proliferation of Asian hornets poses a health, economic and agricultural problem.