Abstract: To reveal the spatial distribution characteristics of the ant species Formica fusca in China, a systematic analysis of its distribution pattern was conducted based on the specimens and related data of geographical distribution, habitats, foraging and nesting sites of the species collected in the field survey from 1995 to 2025. The results showed that Formica fusca was distributed across 14 provincial administrative regions of China. Its horizontal distribution showed a distribution center in the southwest mountainous region and a gradient decrease to the northeast. In vertical distribution, the altitude range of the species was between 165 m and 4 563 m with vertical height difference of 4 398 m, demonstrating a wide ecological amplitude. The collected frequency showed that the species was most concentrated in the mid-altitude range of 2 000-2 499 m. As the altitude increased or decreased, the collected frequency decreased gradually. It indicated that the mid-altitude range was the core distribution area of the species. In terms of habitat, the ant mainly inhabited warm coniferous forest and warm coniferous-broadleaf mixed forest, mainly foraged on the ground, in soil, and on plants, and its nesting sites were mainly under stones and in the soil. Formica fusca preferred temperate and cool environments at medium altitudes. Its high-suitability areas in China were concentrated in the Yunnan-Guizhou Plateau, the southern section of the Hengduan Mountains, and the surrounding areas of the Sichuan Basin. This was closely related to the subtropical humid climate influenced by the warm and moist air currents from the Indian Ocean. The southwest mountainous region of China, characterized by its subtropical climate, complex topography, and diverse microhabitats, was therefore the core distribution area of the species.

Key words: Formica fusca, species, spatial distribution pattern, habitat selection, ecological behavior