Non-native Ants of the Iberian Peninsula: a 2025 Update

The Iberian Peninsula has witnessed a dramatic rise in non-native ant species over the past few decades. This study provides a comprehensive and up-to- date checklist of all introduced ants known from the region as of 2025, based on an exhaustive review of more than 600 published records, over 800 expert- verified citizen-science observations from the platform iNaturalist.org, and over 100 new field records contributed by the authors. All data were manually curated and georeferenced, resulting in the most complete database of non- native ants currently available for the region. A total of 40 non-native species are confirmed, nearly quadrupling the number reported in the last regional review from 2001. Among these, 13 are considered invasive, while the status of 16 others remains uncertain. Most species are associated with disturbed, lowland coastal environments, especially in southern Iberia. Together, the provinces of Barcelona, Sevilla, Cádiz, Almería, and Málaga account for just over half of all recorded occurrences. Although published records from Portugal remain scarce, a substantial number of recent observations from the Algarve and Lisbon regions highlight the growing contribution of citizen science in documenting range expansions across the western Iberian coast. Temporal trends show a sharp acceleration in introductions after 2000, with more species recorded in the 2000s and 2010s than in the entire previous century. Species summaries reveal differing levels of establishment success and potential impact, although most remain confined to human-modified environments such as urban gardens, irrigated parks, and coastal developments. For each species, we provide updated distribution maps, ecological notes, and all known Iberian records. Our findings highlight the need for improved surveillance, standardized data reporting, and long-term monitoring to better understand and manage non-native ant introductions in the region.