Survival of Formosan subterranean termite, Coptotermes formosanus, colonies in seasonally inundated locations of New Orleans, Louisiana

Though Formosan subterranean termite populations survived the prolonged inundation in New Orleans, Louisiana following hurricane Katrina, the survival mechanisms of colonies are not yet understood. One hypothesis is that termite colonies shift their foraging areas, or evacuate, to escape rising flood waters. The movement of colonies in areas exposed to seasonal inundation was observed for two flood seasons and compared to that of colonies not exposed to inundation. Possible vertical movement during flooding was evaluated by sectioning two infested trees located in areas that experience seasonal inundation and determining the height at which termite damage was present. No foraging was observed outside the infested trees at the seasonally inundated locations, while an average of 9 of 50 (18%) of in-ground monitoring stations contained active foraging termites at each unflooded control site. Examination of sectioned trees in inundated locations showed that though termite foraging galleries were present above the water line, carton material was only present in tree sections that had been inundated. These results suggest that in areas which are seasonally flooded, termite colonies do not forage away from rising flood water, but instead remain confined to their food source, and may be protected from flooding by the carton nests.