First records and expanding distribution of a small big-headed ant, Pheidole parva, in Florida, USA

Authors: Ascunce, Marina; BOOHER, DOUGLAS - US Department Of Agriculture (USDA); STOLL, AARON - University Of West Florida; SAN JUAN, AIRLAN - Keyapa; LEE, AGNES - Oak Ridge Institute For Science And Education (ORISE); PORTER, SANFORD - Retired ARS Employee

Submitted to: Neotropical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/30/2026
Publication Date: 7/21/2026
Citation: Ascunce, M.S., Booher, D.B., Stoll, A.C., San Juan, A., Lee, A., Porter, S.D. 2026. First records and expanding distribution of a small big-headed ant, Pheidole parva, in Florida, USA. Neotropical Entomology. 55:66. https://doi.org/10.1007/s13744-026-01416-4.
DOI: https://doi.org/10.1007/s13744-026-01416-4

Interpretive Summary: Due to global trade, many species have been transported outside of their native range and introduced to new areas where they became established as non-native species. Introduced species that have a negative impact on the environment, the economy, or human health are considered invasive species. Invasive species may displace native fauna, reduce biodiversity, impair ecosystem services, serve as pathogen vectors, or are pathogens themselves. Florida is home to many non-native as well as invasive species. In this study, scientists from USDA-ARS, CMAVE, Gainesville, FL and collaborators from USDA-Forest Service and local universities confirm the presence of a new non-native ant, Pheidole parva, a small big-headed ant. The study includes curated iNaturalist observations started in 2017, taxonomical identification and DNA barcoding from ants collected since 2023. This small ant is native to the Indomalaya region and has been affecting mostly Old Word countries for more than 100 years. In Florida, this ant was recorded in 2017 and represents the first report of this ant in North America. In this region, this non-native ant has been observed in close proximity to two main invasive ants: Solenopsis invicta and Pheidole megacephala. Our study highlights the continued spread of non-native ants in Florida, as well as the relevance of citizen science through online platforms such as iNaturalist to help in the early detection of non-native species.

Technical Abstract: Pheidole parva Mayr (1865) is a small ubiquitous ant native to the Indomalayan region where it is considered a pest in healthcare facilities. This tramp ant was first reported outside its native range more than 100 years ago in the Seychelles Islands. Since then, it has been found in other areas of the Old World, where it was likely accidentally introduced via trading ships. In the 2000s this ant was detected in Japan (2001), the Arabian Peninsula (2009) and recently in the Mediterranean island of Cyprus (2023) and Lebanon (2025). Here, we describe its first occurrence in North America, in the state of Florida where both Nearctic and Neotropical realms meet. Our findings are based on recent Pheidole parva specimens collected throughout the state, curated iNaturalist observations, AntWeb data, and DNA barcoding based on the mitochondrial cytochrome oxidase subunit I (COI) gene. Among the 26 P. parva specimens analyzed from Florida, we found three different COI haplotypes. Two of them were also found in other introduced areas; however, one of the haplotypes has only been detected in a native population. The three haplotypes were distributed throughout the state with no clear geographical structure, supporting the idea of recent and probably multiple introductions followed by a rapid expansion of this non-native ant in Florida.