Metabolism of 1,8-cineole in tea tree (Melaleuca alternifolia and M. linariifolia) by pyrgo beetle (Paropsisterna tigrina)

The frass of the pyrgo beetle (Paropsisterna tigrina) feeding on commercial plantations of the terpinen-4-ol chemical variety of the Australian tea tree, Melaleuca alternifolia, was found to contain a volatile oil almost identical to the essential oil of the ingested leaf. When beetles were fed leaf containing substantial quantities of 1,8-cineole, the predominant frass metabolite as determined by MS, IR, C-13 and H-1 NMR, GC, and CoGC was (+)-2beta-hydroxycineole. Both male and female adults and larvae metabolized Melaleuca oils in similar ways