In the autumn, bedbugs primarily seek a refuge to survive the winter and sometimes gather in groups of ten around windows. Among them, the Asian bedbug is becoming increasingly prevalent in France. Originating from Asia, this invasive species takes advantage of warm seasons to multiply its population before attempting to enter homes. Since the end of the summer of 2026, reports of insects clustering on building facades have increased in Western Europe. France's INRAE, a national research institute, is monitoring this phenomenon through its network of citizen science. These bedbugs flee the cold and seek a warm refuge, but not all of them are local species. The Asian bedbug, which arrived in Asia about fifteen years ago, is now swelling these gatherings, which become larger every year due to the warm seasons. When the days shorten and the thermometer drops, these bedbugs enter diapause, a winter metabolic pause, and leave the tree bark and leaf piles for a safer shelter. A south-facing facade, a crack in a wall, a window frame, or a slat on a shutter is sufficient for them. They do not reproduce there and do not eat during the winter, they simply wait for spring. The movement begins as early as mid-September, and it becomes massive because these insects emit an aggregation pheromone that gathers their kin on the most hospitable sites. Originating from East Asia, this invasive species was first detected in France at the beginning of the 2010s, before spreading to most of the country in 2018. It can be identified by its marbled brown back and the two thin light bands that decorate its antennae. A female lays a few hundred eggs and can produce two generations per year when the season is mild, so that a hot and dry summer causes a surge in numbers the following autumn. In gardens and orchards, it pierces more than 120 plants, from apples to walnuts, and has already caused damage in the Rhône valley. Global warming is pushing other Mediterranean and North American bedbugs northward, adding new faces to these gatherings every year. Let us reassure residents, these bedbugs do not bite, do not transmit any disease and are not parasites, the German environmental agency classifies them as simple nuisances. Their only weapon is chemical, because disturbed or crushed, they release a pungent coriander-like odor that sticks to fingers and fabrics. It is therefore better to collect them with a handkerchief or to suck them up, then empty the bag immediately. To prevent them from entering, authorities recommend installing mosquito nets, sealing cracks in walls, and inspecting firewood before bringing it indoors, as a log can shelter an entire dormant colony.