Over 15,000 species of ants have been described, and more than 200 have established populations outside of their native ranges. A small subset of these have become highly destructive invaders including the Argentine ant (Linepithema humile), the big-headed ant (Pheidole megacephala), the crazy ant (Anoplolepis gracilipes), the little fire ant (Wasmannia auropunctata), and the red imported fire ant (Solenopsis invicta) which are currently listed among the world’s 100 worst invasive species (Lowe 2000). Additionally, two of these species (Linepithema humile and Solenopsis invicta) are among the four most well studied invasive species generally (Pyšek et al. 2008). Although invasive ants are economically costly in both urban and agricultural areas, the most serious consequences of their introduction may be ecological. Invasive ants can greatly modify ecosystems by reducing native ant diversity, displacing other arthropods, negatively impacting vertebrate populations, and disrupting ant-plant mutualisms.
Invasive ants form a small and somewhat distinct subset of ants introduced into new environments by humans. A majority of introduced ants remain confined to human-modified habitats and some of these species are often referred to as tramp ants because of their reliance on human-mediated dispersal and close association with humans generally. Although hundreds of ant species have become established outside of their native ranges, most research has concentrated on the biology of only a few species.
Here are some useful references for further reading on introduced and invasive ants.
Deyrup, M. Davis, L. and Cover, S. 2000. Exotic ants in Florida. Transactions of the American Entomological Society 126:293-326. | full citation
Economo, E.P. and Sarnat, E.M. 2012. Revisiting the ants of Melanesia and the taxon cycle: historical and human-mediated invasions of a tropical archipelago. American Naturalist 180:E1-E16. | full citation
Holldobler, B. and Wilson E.O. 1990 The Ants. Belknap, Cambridge, MA. | full citation
Holway D.A., Lach L., Suarez A.V., Tsutsui N.D., Case T.J. 2002. The causes and consequences of ant invasions. Annual Review of Ecology and Systematics 33:181–233. | full citation
Krushelnycky, P.D., Loope, L.L., and Reimer, N.J. 2005. The ecology, policy, and management of ants in Hawaii. Proceedings of the Hawaiian Entomological Society. 37:1-25. | full citation
Lach, L. 2003. Invasive ants: unwanted partners in ant-plant interactions? Annals of the Missouri Botanical Garden 90:91-108.| full citation
Lach, L. and Thomas, M.L. 2008. Invasive ants in Australia: documented and potential ecological consequences. Australian Journal of Entomology. 47:275-288. | full citation
Lester, P.J. 2005. Determinants for the successful establishment of exotic ants in New Zealand. Diversity and Distributions 11:279-288. | full citation
Lessard, J.P., Fordyce, J.A., Gotelli, N.J., and Sanders, N.J. 2009. Invasive ants alter the phylogenetic structure of ant communities. Ecology 90:2664-2669. | full citation
Lowe, S., Browne, M. & Boudjelas, S. 2000. 100 of the world’s worst invasive alien species - a selection from the Global Invasive Species database). The Invasive Species Specialist Group (ISSG) of the Species Survival Commission (SSC) of the World Conservation Union (IUCN), Switzerland. | full citation
McGlynn T.P. 1999. The worldwide transfer of ants: geographical distribution and ecological invasions. Journal of Biogeography 26:535–548. | full citation
Moller H. 1996. Lessons for invasion theory from social insects. Biological Conservation 78:125–142. | full citation
Ness, J.H. and Brunstein, J.L. 2004. The effects of invasive ants on prospective mutualists. Biological Invasions 6:445-461. | full citation
Pyšek, P., Richardson, D.M., Pergl, J., Jaroaík, V.c., Sixtová, Z. & Weber, E. 2008. Geographical and taxonomic biases in invasion ecology. Trends in ecology & evolution 23: 237-244. | full citation
Rabitsch, W. 2011. The hitchhiker’s guide to alien ant invasions. BioControl 56:551-572. | full citation
Rizali, A., Lohman, D.J., Buchori, D., Prasetyo, L.B., Triwidodo, H., Bos, M.M., Yamane, S. and Schulze, C.H. 2010. Ant communities on small tropical islands: effects of island size and isolation are obscured by habitat disturbance and ‘tramp’ ant species. Journal Of Biogeography 37:229-236. | full citation
Suarez A.V., Holway D.A., Ward P.S. 2005. The role of opportunity in the unintentional introduction of nonnative ants. Proceedings of the National Academy of Sciences USA 102:17032–17035. | full citation
Tsutsui, N.D., and Suarez, A.V. 2003. The colony structure and population biology of invasive ants. Conservation Biology 17:48-58. | full citation
Ward, D.F., Beggs, J.R., Clout, M.N., Harris, R.J., and O’Connor, S. 2006. The diversity and origin of exotic ants arriving in New Zealand via human-mediated dispersal. Diversity and Distributions. 12:601-609. | full citation