Reinvasion and colony expansion of Coptotermes formosanus (Isoptera: Rhinotermitidae) after areawide elimination

Abstract

The population recovery of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) colonies were monitored after an areawide elimination of all detectable colonies from September 2003 to August 2005 in Louis Armstrong Park, New Orleans, LA. Six colonies reinvaded the vacant niche created by the full elimination. These colonies expanded their territories throughout the study period. This represented 43% of the original number of colonies present in the park before the elimination. To determine the mode of the reinvasion, nuptial pair establishment was monitored during the C. formosanus dispersal flight seasons. Nuptial pairs were discovered up to 1 yr after the elimination. Morphological and genetic data were collected from field colonies before the full elimination in 2002 and again in 2005 after the reinvasion of these territories by new colonies. These data were used to estimate the relative age of reinvading colonies as compared with their predecessors. It is proposed that the first three reinvading colonies detected were smaller colonies that were undetectable before the full elimination, or were older, established colonies present outside of the park, that expanded their foraging territories into the park in the absence of competition from the eliminated populations. The subsequent three colonies to reinvade seemed to be small colonies founded during or just before the study period by an imago pair after a dispersal flight into the park from outlying areas. The implications of this study on subterranean termite areawide integrated pest management strategies are discussed.