Master of Science (MS)
The Formosan subterranean termite, Coptotermes formosanus Shiraki, an invasive species from southern China, is one of the most destructive wood pests in the United States. Presently, termites are managed through chemical control. However, some synthetic chemicals cause serious environmental problems due to their persistence and toxicity. There is growing interest in using natural compounds with low toxicity to mammals to control termites. Trans-caryophyllene is a component of essential oil found in many flowering plants. It is especially abundant in clove oil. It has also been found to be released from the roots of maize damaged by insects. I investigated caryophyllene as a potential control agent for Formosan subterranean termites. I evaluated caryophyllene topical toxicity, consumption of treated filter paper in choice and no choice tests, and effect on Formosan termite tunneling behavior. Caryophyllene was moderately toxic to Formosan subterranean termites (LD50 =40.19 ug/insect; 95% CL 28.36-53.74 ug/insect). In no choice consumption tests, termite feeding was negatively correlated with dose of caryophyllene. In multiple choice bioassays, greater consumption occurred on untreated filter paper, suggesting caryophyllene is not a feeding stimulant, but may in fact act as a repellent. Equal tunnel volumes were recorded in chambers with or without caryophyllene but loctaion of tunneling suggested an effect on tunnel orientation behavior and attraction to caryophyllene. However, tunnel volume increased significantly toward the center of areas where caryophyllene droplets were placed, but in untreated chamber, tunnel volume increased mainly along the edges of the chamber. These results indicate that while caryophyllene shows moderate acute toxicity to Formosan subterranean termites and paper treated with this sesquiterpene is a feeding deterrent, termites will tunnel toward caryophyllene droplets. Further studies are needed to evaluate caryophyllene’s effectiveness when used against termites.
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Qi, Qiaoling, "Survivorship, tunneling and feeding behaviors of Formosan subterranean termite (Isoptera: Rhinotermitidae) in response to trans-caryophyllene" (2009). LSU Master's Theses. 715.