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Thaumetopoea pityocampa (Denis & Schiffermüller, 1775) (Lepidoptera:Notodontidae ) is the most important defoliating insect for several pine species and cedars. In this study, body nutrient composition of T. pityocampa larvae were analyzed under feeding inhibition caused by natural chemical agents. In no-choice assays, larvae were fed ponderosa pine needles treated with oleic acid and chlorogenic acid solutions, respectively, at each of four concentrations, 0%, 25%, 50% and 75%. The neetles were as given to separate test groups. At the end of feeding experiments, antifeedant index (AFI) was calculated for each solutions with different concentrations. Then, rates of protein, lipid, glycogen and water of larvae were calculated for control and test groups. It was determined that there had been a strong relation between concentrations of solution and AFI values regarding oleic acid (r= 0.998, P < 0.05). However, there was no significant relationship between concentrations of solution and AFI values regarding chlorogenic acid (r= 0.663, P > 0.5). The most remarkable finding was a sharp decline in the level of larval glycogen during starvation period in accordance with rising concentrations of both oleic and chlorogenic acid in its food. The glycogen level of the larvae was also affected by both chemical applications |
