Seasonal Occurrence of Swarming Activity and Worker Abundance of Pachycondyla Chinensis

Abstract:
The introduced ant, Pachycondyla chinensis (Emery) (Hymenoptera: Formicidae) is a pest in northwestern South Carolina, and areas of North Carolina and Tennessee in the United States. First documented in the United States over 70 years ago, it only recently has achieved pest status. This exotic species originating from Asia, poses a health threat because of allergic reactions elicited by its sting. Pachycondyla chinensis also may pose a threat to ant communities in locations where it occurs. In the study reported here we assessed the seasonal occurrence of P. chinensis workers and alates in northwestern South Carolina USA. Pitfall traps were established in three locations in or near Clemson, SC USA to collect P. chinensis workers from January 2007 through March 2008. Worker activity was documented in January, but consistent activity was not recorded until late March. Ant worker activity began declining in September, was inconsistent in October, and by November, workers were no longer present in pitfall traps. Ground-dwelling colonies were not observed after this time. Light traps were operated in three locations in or near Clemson, SC USA from March through November 2007. We determined that P. chinensis began swarming in late May, peaked in mid-July and declined sharply by early August. Minimal swarming continued into September. Male alates were differentially captured in light traps by a mean ratio of 19.:1..