tramp ant

Etymology
From +, because they are often inadvertently carried on ships.

Noun

 * 1) Any of various invasive species of ant often inadvertently transported in soil with cargo on ships, trains, etc.
 * 2) * 2004, S. Bradleigh Vinson, Sean T, O'Keefe, Gordon W. Frankie, Chapter 6: The Conservation Values of Bees and Ants in the Costa Rican Dry Forest, G. W. Frankie, Alfonso Mata, S. Bradleigh Vinson (editors), Biodiversity Conservation in Costa Rica, page 67,
 * The occurrence of highly invasive (tramp) ants (Passera 1994) is of concern, and Saks and Carroll (1980) showed that tramp ants could become abundant in disturbed areas while remaining uncommon in nearby undisturbed forests. Exotic tramp ant species have been found to produce major changes in abundance and diversity of invertebrate species in other regions (Lubin 1984; Zenner-Polania 1994).