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Submitted to: Sociobiology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/1/2005 Publication Date: 2/1/2005 Citation: Morales Ramos, J.A., Rojas, M.G. 2005. Wood consumption rates of coptotermes formosanus(isoptera: rhinotermitidae): a three - year study using groups of workers and soldiers. Sociobiology 45:707-719. Interpretive Summary: The Formosan subterranean termite is the most destructive of the subterranean termite species currently inhabiting the United States. The larger size of colonies and foraging territories of the Formosan termites are some of the reasons for their great destructive potential. This destructive potential is particularly linked to the feeding rates of these subterranean termites. Developing methods to study feeding rates of the Formosan subterranean termite would help on the development of new methods for evaluating and predicting the potential damage inflicted by this pest. This would allow a more accurate account of the potential economical impact of this pest and improve the chances for control. The objective of this study was to develop a new method to determine per capita consumption rates of Formosan subterranean termite workers under a controlled environment as a basis for future development of a simulation model to predict potential damage by this insect pest. The advantages of this new method over previously available methods for determining consumption rates include 1) requires the use of a simple linear model reducing the complexity of required calculations, 2) estimations are obtained independently of termite weight allowing comparisons of feeding rates of termites of different sizes, 3) estimates per capita consumption rates in a more direct manner than other methods. Results showed that the data fitted the linear model better than adequately supporting the validity of this new method. Wood consumption was significantly higher when termites fed on loblolly pine than when they fed on birch. This difference may be due to the higher specific gravity or hardness of birch wood as compared to loblolly pine wood. Termite groups were kept for a period longer than 2 years without developing supplementary reproductives. This indicates that some special conditions are needed for the development of supplementary reproductives from termite workers. This study is potentially beneficial to termite science, pest control companies, pest control industry, and to the public. Technical Abstract: Estimates of per capita consumption rates of subterranean termites are important for future modeling of termite damage over time. A new method was developed to estimate per capita wood consumption rates of Coptotermes formosanus Shiraki using a linear regression model of decline of termite group consumption rates over time. Wood consumption of termite groups of 200 workers and 50 soldiers was measured over time intervals of 2 mo at 27°C, 95% RH, at constant darkness for their entire life span. Consumption of wood was compared among termite groups feeding on yellow birch, Betula alleghaniensis Britton, and loblolly pine, Pinus taeda L. Linear fit of termite group wood consumption and pivotal group age was adequate and lack of fit test was not significant. Per capita consumption rates were 86.9 ± 2.2 and 101.3 ± 1.2 µg/d for birch and loblolly pine food treatments, respectively. Wood consumption was significantly higher in the loblolly pine treatment, but group longevity and individual mortality rates were not significantly different between treatments. Differences in consumption rate may have been due to differences in wood hardness rather than feeding preferences. Mean longevity of termite groups was 518.3 ± 46.5 d and 584.3 ± 51.1 d for the yellow birch and loblolly pine treatments, respectively. Approximately 30% of the termite groups exceeded a 2 y longevity; however, no termites differentiated into neotenic reproductives in any of the groups. Special conditions, not met in this study, may be required for the development of neotenic reproductives in C. formosanus. |
