The worldwide transfer of ants: geographical distribution and ecological invasions

Abstract

Summary: Aim This is the first comprehensive account of the biogeography of ants transferred and at least temporarily established outside their native habitat. Location Using museum and literature records, I established the distributions of transferred ant species. Methods I used taxonomic and functional groups to assess how geographical spread as a transferred species is affected by taxonomy and life history. Results 147 ant species in forty‐nine genera have been recorded outside of their native habitat. The proportion of transferred ants is similar to the number of genera and species in each subfamily. The species‐rich subfamily Myrmicinae contains nearly 50% of all transferred species, while many of the species‐poor subfamilies have absolutely no transferred species. A disproportionate high number of transferred ants originate from the Neotropical and Oriental biogeographic regions. The Pacific Islands are the recipients of the most transferred ant species. Most transferred ants belong to the CRYPTIC, OPPORTUNIST, and GENERALIZED MYRMICINE functional groups, while there are no recorded transfers of army ants or leaf‐cutting ants. Both invasive and human commensal ‘tramp’ ant species are nonrandom subsets of transferred ants. Main conclusions‘Tramp’ species and invasive species tend to have widespread geographical distributions, and share life history characteristics including queen number, nest structure, and foraging behaviour. Combining observations of functional groups and biogeography may lead to a better understanding of the factors contributing to the spread of transferred species.