Cyanoglycoside gynocardin fromAcraea horta (L.) (Lepidoptera: Acraeinae) : Possible implications for evolution of acraeine host choice.

All stages in the life cycle ofAcraea horta (L.) (Lepidoptera: Acraeinae) were found to release hydrogen cyanide (HCN) from their crushed tissues, and the source of cyanogenesis was present in the hemolymph of adults and larvae. Comparison with standards on thin-layer chromatograms (TLC) revealed the presence in adults of gynocardin, a cyclopentenyl cyanoglycoside also produced by the larval food plant,Kiggelaria africana L. (Flacourtiaceae). Analysis of adults reared on plant species (Passifloraceae) containing gynocardin and/or other cyanoglycosides suggested selective uptake of gynocardin by the larvae. This is the first demonstration of a cyanoglycoside, other than the acyclic linamarin and lotaustralin, occurring in Lepidoptera and the first evidence for the storage byAcraea butterflies of a plant-produced allelochemical. Possible implications for the understanding of the evolution of acraeine host choice are discussed.