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Subterranean termite behavioral reaction to water and survival of inundation: implications for field populations

Forschler, B.T., Henderson, G.
Environmental entomology 1995 v.24 no.6 pp. 1592-1597
animal behavior, submergence, saturated conditions, rain, Reticulitermes virginicus, Coptotermes formosanus, mortality, Reticulitermes flavipes, Georgia
Laboratory tests involving termite response to rising water levels demonstrated that subterranean termites (Reticulitermes spp.) do not try to escape being submerged. Studies in which termites were completely submerged in water provided LT50s of 19.6 h for eastern subterranean termites, Reticulitermes flavipes (Kollar), 13.9 h for R. virginicus (Banks), and 11.1 h for, Formosan subterranean termites, Coptotermes formosanus Shiraki. These data suggest that subterranean termites, in the field, escape drowning not by seeking higher ground but by entering a state of quiescence when confronted with excessive amounts of water in their subterranean habitat. Under normal rainfall conditions, water should move through the soil profile within several hours. If this does not occur, then high termite mortality could result. In the summer of 1992, we characterized the foraging populations of 5 subterranean termite colonies using the triple mark-recapture technique. These colonies averaged 99,000 (range, 157,00-14,000) foraging termites per colony. In the spring 1993, these same colonies were recharacterized and their populations averaged 21,000 (range, 53,000-1000) foraging termites per colony. This represents a 77% reduction in the average foraging populations for these colonies. In this article we provide empirical evidence that these population reductions were a result of heavy rainfall in west-central Georgia during the winter of 1992-1993.