Effect of Temperature and Humidity on Survival of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae)

Two subterranean termite species were subjected to combinations of six temperatures (10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, or 35 degrees C) and five relative humidities (RH) (SS, 65, 75, 85, or 99%) to determine optimum conditions for survival. When small groups of the Formosan subterranean termite Coptotermes formosanus Shiraki or the eastern subterranean termite Reticulitermes flavipes (Kollar) were exposed to all 30 combinations of temperature and RH, survival times were significantly influenced by temperature, RH, and their interaction. For both species, survival times were longest at low temperatures and high RH. Maximum survival of small groups of C. formosanus and R. flavipes workers and soldiers occurred at the combination of 10 degrees C and 99% RH C (LT50 = 28.2 d, LT50 = 18.1 d, respectively). Survival of paired C. formosanus dealates was evaluated at combinations of 20 degrees, 25 degrees, or 30 degrees C and 55, 65, 75, 85, or 99% RH. Survival was strongly influenced by temperature and humidity. Longest survival times until 50% mortality occurred at 99% RH and 20 degrees or 25 degrees C (LT50 = 2.5 d, LT50 = 3.0 d, respectively). At all temperatures, mortality occurred too quickly for LT50 values to be determined when RH was 55% or 65%.