Researchers from North Carolina State University have found that one of the most aggressive invasive ant species in the United States the Argentine ant appears to have met its match in the Asian needle ant. Specifically, the researchers have found that the Asian needle ant is successfully displacing Argentine ants in an urban environment, indicating that the Asian needle ant with its venomous sting may be the next invasive species to see a population boom.
In the world of invasive species, the Argentine ant (Linepithema humile) is a success story. Its aggressive, territorial behavior and ability to create huge "supercolonies" consisting of thousands of queens and millions of workers have enabled the Argentine ant to spread across the United States, displacing native species and changing ecosystems to suit its needs. No other ant species had been seen successfully pushing back until now.
In 2008, while watching a supercolony of Argentine ants in an urban environment, former NC State Ph.D. student Dr. Eleanor Spicer Rice noticed that Asian needle ants (Pachycondyla chinensis) were living and working in the area. This was surprising because Argentine ants normally do not tolerate any other ant species in their territory, so Spicer Rice decided to investigate further.
Over the next four years, Spicer Rice found that Argentine ants appeared to ignore Asian needle ants, and the Asian needle ants took advantage of the situation to displace a significant portion of the Argentine ant population. In 2008, Argentine ants had populations in 99 percent of the sites within the study area, while only 9 percent of the sites were home to Asian needle ant populations. By 2011, Argentine ants were found in only 67 percent of the sites while the Asian needle ants had expanded to occupy 32 percent of the sites. The two ant species shared 15 percent of the sites in common.
"This is the first time we've seen another ant
|Contact: Matt Shipman|
North Carolina State University