Concentration-Dependent Feeding Deterrence to 20-Hydroxyecdysone for Three Subterranean Termite Species (Blattodea: Rhinotermitidae)

• Main Authors: Lucas Carnohan, Sang-Bin Lee, Nan-Yao Su
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Insects
• Subjects: termite bait; hyperecdysonism; <i>C. formosanus</i>; <i>C. gestroi</i>; <i>R. flavipes</i>
• Online Access: https://www.mdpi.com/2075-4450/12/3/218

Effective active ingredients in toxicant bait formulations must be non-deterrent to insect feeding behavior at lethal concentrations. This study evaluated feeding deterrence for <i>Coptotermes formosanus</i> Shiraki, <i>C. gestroi</i> (Wasmann), and <i>Reticulitermes flavipes</i> (Kollar) when provided access to cellulose impregnated with various concentrations of the insect molting hormone, 20-hydroxyecdysone (20E). Termites were exposed to 20E concentrations of 200, 500, 1000 and 2000 ppm and to noviflumuron at 5000 ppm in a 24 h choice-test, and the mass of substrate consumption from treated and untreated media pads was compared for each treatment. 20E feeding deterrence was detected at 500, 1000 and 2000 ppm for <i>C. gestroi</i>, and at 2000 ppm for <i>C. formosanus</i>. No significant differences in consumption of treated and untreated substrate was detected at any concentration for <i>R. flavipes</i>. Potential methods for reducing deterrence are discussed.