Colorado potato beetle, metabolism

Differences in the transport and metabolism do not seem to play an important role in tebufenozide s lack of toxicity to coleopteran species. Studies in which a highly susceptible caterpillar species (Spodoptera eridania) and a non-susceptible larval beetle species (Mexican bean beetle, Epilachna varivestis) were fed equal amounts of Relabelled tebufenozide showed surprisingly similar patterns of tebufenozide uptake, metabolism, and overall tissue distribution (13). The minor differences observed in this study were clearly insufficient to account for the greater than 2,800-fold difference in tebufenozide susceptibility between these two species (LC50 = 0.7 ppm for Spodoptera, >2,000 ppm for Epilachna) (12). Studies comparing beet armyworm (Spodoptera exigua) with Colorado potato beetle (Leptinotarsa decemlineata) yielded similar results (15). 

Although much is already known about the metabolic pathways of fenvalerate in mammals, plants, and soils, its fate in insects had not been much investigated. Colorado potato beetle was the test organism of a metabolism study in which about 20 metabolites were separated and characterized. Seven different elution systems, with one- or two-dimensional TLC or several developments in the same direction using the same mobile phase, were applied to the separation of the metabolites. Some of them are listed in Table 9 (122). Degradation of cis- and rruns-permethrin in flooded soil was studied using carbonyl- C-cis-, carbonyl- C-trans-, and methylene- C-cis-permethrin. The TLC analysis (123) (Table 9) of soil and water extracts showed a faster degradation of tra/ts-permethrin than of CIS-derivative. 

Keck, P. S. Sims, and D. Bartnicki. 1993. Assessment of the Metabolic Degradation of the Colorado Potato Beetle (CPB) Active Protein in Simulated Mammalian Digestive Models Lab Project Number 92-01-37-16 93-08IE. Unpubhshed study prepared by Monsanto Co. 145 p. 

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