Introduced by accident in France in the early 2000s, the yellow-legged hornet—also known as the Asian hornet—has now been reported in every department of the country, according to the French Ministry of Agriculture. This insect is classified as an invasive exotic species, meaning it is not native to France and can have harmful effects on local ecosystems. Entomologist Serge Gadoum notes that the species has "rather well withstood" recent heat waves and is currently in its mating season. A national plan to limit the hornet’s impact on biodiversity and agriculture was officially published in the Journal officiel last Wednesday. The Asian hornet is particularly active in September, a time when it reproduces and increases its predation on domestic bees. This month has seen several incidents, including a group of 37 hikers attacked in the Haute-Vienne region and a dozen cyclists stung in the Morbihan. However, it is still too early to determine if the population has grown compared to last year. According to Serge Gadoum, the hornet’s life cycle is influenced by weather conditions. Colder summers increase mortality rates, but this year, the mild winter of 2025-2026 allowed future queens to survive hibernation and begin laying eggs early. Climate change has played a role in the hornet’s spread, according to Hugo Arsan of the Fredon Ile de France network. Warmer conditions have facilitated the species’ establishment and growth in France. While the hornet can handle high temperatures, its activity may decrease if temperatures exceed 40°C, before resuming in September. Despite the recent heat, the species has remained active, which explains why people are encountering it more often at the start of the school year. However, the hornet only stings when physically threatened, according to the OPIE (Office for Insects and Their Environment). Over the past few years, the yellow-legged hornet has expanded its range northward and eastward across France. In areas where it is still new, the species has experienced a population boom. Entomologists predict that these populations will eventually peak and then decline before stabilizing. The national plan published last week aims to manage this growing presence and mitigate its impact on local biodiversity and agricultural practices.