Ants are conspicuous components of most terrestrial ecosystems. Ants are important predators, scavengers, granivores, and in the new world, herbivores. Ants also engage in an astonishing array of associations with plants and other insects, and can act as ecosystem engineers as agents of soil turnover, nutrient redistribution, and small-scale disturbance.
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 yellow 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 et al. 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.
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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.
- 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.
- Holldobler B. and Wilson E.O. 1990 The Ants. Belknap, Cambridge, MA.
- Holway D.A., Lach L., Suarez A.V., Tsutsui N.D., and Case T.J. 2002. The causes and consequences of ant invasions. Annual Review of Ecology and Systematics 33:181–233.
- 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.
- Lach, L. 2003. Invasive ants: unwanted partners in ant-plant interactions? Annals of the Missouri Botanical Garden 90:91-108.
- Lach L. and Thomas M.L. 2008. Invasive ants in Australia: documented and potential ecological consequences. Australian Journal of Entomology. 47:275-288.
- Lester P.J. 2005. Determinants for the successful establishment of exotic ants in New Zealand. Diversity and Distributions 11:279-288.
- 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.
- Lowe S., Browne M., and 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.
- McGlynn T.P. 1999. The worldwide transfer of ants: geographical distribution and ecological invasions. Journal of Biogeography 26:535–548.
- Moller H. 1996. Lessons for invasion theory from social insects. Biological Conservation 78:125–142.
- Ness J.H. and Brunstein, J.L. 2004. The effects of invasive ants on prospective mutualists. Biological Invasions 6:445-461.
- Pyšek P., Richardson D.M., Pergl J., Jaroaík V.C., Sixtová Z., and Weber E. 2008. Geographical and taxonomic biases in invasion ecology. Trends in ecology & evolution 23: 237-244.
- Rabitsch W. 2011. The hitchhiker’s guide to alien ant invasions. BioControl 56:551-572.
- 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.
- Suarez A.V., Holway D.A., and 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.
- Tsutsui N.D. and Suarez A.V. 2003. The colony structure and population biology of invasive ants. Conservation Biology 17:48-58.
- 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.
