Survivorship of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in a Hypoxic Environment

Abstract

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a structural pest of major economic importance in the city of New Orleans, Louisiana.  Hurricane Katrina made landfall along the United States Gulf coast on August 29, 2005, inundating approximately 80% of the city.  Though termite colonies survived prolonged inundation, the survival mechanisms of colonies have yet to be fully understood.  One hypothesis is that C. formosanus colonies survived within pockets of trapped air within their nesting system during times of flooding.  This hypothesis was tested by measuring mortality of groups of 20, 40, and 60 termites in airtight environments maintained at three different temperatures.  Groups of 20 termites maintained at 10, 21, and 32°C reached 100% mortality at 89.5, 52.0, and 3.5 days, respectively.  Groups of 40 termites maintained at 10, 21, and 32°C reached 100% mortality at 89.5, 51.0, and 3.5 days, respectively.  Groups of 60 termites maintained at 10, 21, and 32°C yielded 100% mortality at 57.5, 22.5, and 1.0 day, respectively.  Field colonies of C. formosanus established before Hurricane Katrina survived up to three weeks of flooding, and our findings suggest that is possible for inundated colonies to survive this prolonged flooding by remaining within air pockets located in their nesting system until flood waters recede.