Submitted to: International Society of Chemical Ecology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 8/17/2008
Publication Date: N/A
Technical Abstract: Fatty acid amino acid conjugates (FACs) are known elicitors of induced release of volatile compounds in plants that, in turn, attract foraging parasitoids. Since the discovery of volicitin [N-(17-hydroxylinolenoyl)-L-glutamine] in the regurgitant of larval Spodoptera exigua1, a series of related FACs have been identified in several other lepidopteran species. When screening 13 non-lepidopteran insects for the presence of FACs we identified the same variety of FAC analogs previously found in lepidopteran caterpillars (N-linolenoyl- and N-linoleoyl-L-glutamic acids (main components), glutamine conjugates and hydroxylated derivatives of these corresponding FACs, including volicitin) in gut extracts of two closely related cricket species, Teleogryllus taiwanemma and T. emma (Orthoptera: Gryllidae), as well as in larval fruit fly, Drosophila melanogaster (Diptera: Drosophilidae). This suggests that FACs are more common than earlier thought and may have physiological roles through a wide range of insects. In a previous study, we demonstrated that glutamine conjugates play an active role in nitrogen metabolism in S. litura larvae (manuscript in preparation). However, a physiological role or biosynthetic pathway has yet to be established for glutamic acid conjugates which are the major FAC components in crickets and fruit fly as well as in Manduca sexta (Lepidoptera). Here we report an intriguing biosynthetic pathway of glutamic acid conjugates in T. taiwanemma, which might help us to understand why some insects have evolved such a variety of FACs while other species have not.