Author
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Wiltz, Beverly |
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Submitted to: Sociobiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/1/2011 Publication Date: 5/21/2012 Citation: Wiltz, B.A. 2012. Effect of temperature and humidity on survival of coptotermes formosanus and reticulitermes flavipes (Isoptera: Rhinotermitidae). Sociobiology. 59(1):381-394. Interpretive Summary: Temperature and moisture are key factors affecting termite survival, activity, and geographic distribution. Effects of soil moisture on feeding and tunneling activity have been extensively studied. Other studies have linked relative humidity to the survival and activity of arid climate species and determined optimum temperature-humidity combinations for feeding. Termites are well adapted to regulating moisture within the nest, thus limiting the possibility for direct effects of relative humidity on colony survival. However, humidity may indirectly influence subterranean termite success by affecting the ability of soil and wood to retain moisture. This study was to determine the combined effects of temperature and relative humidity on survival of two subterranean termite species: Coptotermes formosanus and Reticulitermes flavipes. Both species survived longest at the lowest temperature and highest relative humidity tested. In addition, temperature and humidity strongly influenced the survival times of C. formosanus reproductives. Technical Abstract: Two subterranean termite species were subjected to combinations of six temperatures (10°, 15°, 20°, 25°, 30°, or 35°C) and five relative humidities (RH) (55, 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°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°, 25°, or 30°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° or 25°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%. |
