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Submitted to: Sociobiology
Publication Type: Proceedings Publication Acceptance Date: 7/20/2004 Publication Date: 6/1/2005 Citation: Morales Ramos, J.A., Rojas, M.G. 2005. Wood consumption of young colonies of coptotermes formosanus (isoptera: rhinotermitidae). Sociobiology. Interpretive Summary: The Formosan subterranean termite (Coptotermes formosanus Shiraki) is the most destructive subterranean termite species in the United States, producing millions of dollars in structural damage annually. This invasive termite is more destructive than native termite species because of its greater wood consumption rates. The wood consumption of the Formosan subterranean termite has been studied in the past by using groups of termite workers collected from the field. These field collections usually consist of a limited diversity of termite stages and older soldiers. But what happens to the rest of the colony? This study is the first attempt to study the consumption rates of full colonies of the Formosan subterranean termite by using young (2-year-old) colonies. The use of young colonies allow for a large number of observations for statistical analysis and under controlled environment with limited space. The wood consumption of 150 termite colonies of known size was measured by determining the weight loss of pieces of red gum wood exposed to the termite colonies for periods of 60 days. Statistical analysis was then used to find correlation between the presence of certain termite caste and the increase or decrease in colony wood consumption. Our studies showed that soldier numbers, even though they are incapable of feeding themselves, impact the colony wood consumption rates by increasing it. This indicates that termite workers must work harder consuming more wood in order to feed an increasing number of soldiers. Technical Abstract: Wood consumption ratesof young (2 years-old) colonies of Coptotermes formosanus Shiraki were measured. Termite colonies were reared in the laboratory from alates captured with an UV light trap in New Orleans during May 2001. Paired dealates were reared in artificial diet for 1 year and then transferred to plastic boxes provided with wood, soil, and water. When colonies reached 26 months of age, boxes were opened to count the number of individuals per colony and record it. A total of 150 colonies of known size were transferred to new plastic boxes and were provided with soil, water, and pieces of red gum (Liquidambar styrasiflua L.). The wood pieces were dried in a vacuum oven, weighted and exposed to the termite colonies for periods of 60 days at 27 ± 1°C, 93% RH, and total darkness. Consumption rate was calculated (in mg/day) by weight loss of wood pieces after exposure to the colonies. Data consisting of caste counts and percentages and wood consumption rates were analyzed by linear regression. Analysis showed that the number of mature individuals per colony and soldier proportion correlated with consumption rates. Stepwise analysis indicated that the best linear model explaining colony wood consumption rates included number of workers and percent soldiers as independent variables. These results suggest that soldier percentage significantly impact worker foraging rates in C. formosanus. |
