RT Journal Article T1 Quick spreading of populations of an exotic firefly throughout Spain and their recent arrival in the French Pyrenees A1 Koken, Marcel A1 Guzmán Álvarez, José Ramón A1 Gil Tapetado, Diego A1 Romo Bedate, Miguel Angel A1 Laurent, Geneviève A1 Rubio, Lucas Ezequiel A1 Rovira Comas, Segimon A1 Wolffler, Nicole A1 Verfaillie, Fabien A1 De Cock, Raphaël AB In August 2018, a firefly (Coleoptera: Lampyridae) of American origin was observed in several localities in Girona (Catalonia, Spain) and was described as Photinus immigrans by Zaragoza-Caballero and Vinolas, 2018. Here, we show that this species dispersed very quickly throughout northeastern Spain and was, in 2020, observed in the French Pyrenees. The animal’s quick progress is documented, and part of its biology is described (dispersion speed, land use, phenology, identification of all life stages). An additional population was localized in Extremadura, and its special status is discussed. We were able to determine its Argentinian–Uruguayan origin and propose, therefore, to consider Photinus immigrans as a synonym of Photinus signaticollis (Blanchard, 1846) (=Photinus immigrans Zaragoza-Caballero and Viñolas, 2018, syn. nov.). Our data clearly show that at least the Catalan and French populations are spreading very quickly and are able to settle permanently if adequate ecosystems are found. The species is highly expansive and may well be invasive; our citizen science platforms are ideally suited to monitor their progress throughout Spain and France. This is important for avoiding future ecological problems with diverse native faunas, such as glow-worms, fireflies and earthworms. If no ways are found to stop the species’ progression, the animals will quite probably invade substantial areas of France, Spain and the rest of Europe in the years to come. PB MDPI SN Electronic: 2075-4450 YR 2022 FD 2022-01-29 LK https://hdl.handle.net/20.500.14352/71759 UL https://hdl.handle.net/20.500.14352/71759 LA eng DS Docta Complutense RD 18 abr 2025