As summer winds down, France is experiencing a noticeable increase in mosquito activity, with some regions reporting a shortage of mosquito repellent products. In Nantes, a store manager told TF1 that the repellent aisle was "stripped bare in two days," an unusual situation that highlights the sudden surge in demand. Many social media users have also shared stories of recent bites, despite having gone through much of the summer without encountering many insects. Current weather conditions across France remain mild, with temperatures ranging from 21°C in Paris to 28°C in Marseille and Perpignan. Anna-Bella Failloux, an entomologist at the Pasteur Institute, explained that while it's difficult to measure mosquito populations accurately, the development cycle of the Culex pipiens mosquito — the most common species in France — is affected by temperature. At 25°C, their life cycle lasts about ten days, but it can be shortened to seven days in hotter conditions. However, extreme heat can also be fatal to these mosquitoes if they can't find cooler areas, as they lack the ability to regulate their internal temperature. The tiger mosquito, known for its distinctive black and white stripes, is also becoming more prevalent. Unlike the Culex pipiens, whose eggs cannot survive dry conditions, tiger mosquito eggs can remain dormant for months in dry and cold environments. After a particularly dry summer, tiger mosquitoes may have been less active in June, July, and August. However, recent rains and still-mild temperatures have allowed them to regain their activity, with a second peak in numbers typical for this time of year, according to meteorologist Régis Crêpet. Tiger mosquitoes have been steadily spreading across mainland France since 2005, with their presence monitored annually through traps. While it's still too early to determine if 2026 will be an exceptional year for their spread, Failloux warned that a mild autumn and winter could extend their presence beyond November. To reduce mosquito populations, both in summer and autumn, the best approach is to eliminate any containers that can collect stagnant water near or inside homes, as these are ideal breeding grounds for mosquitoes.