Oviposition stimulant of a Zeryntiine swallowtail butterfly, Luehdorfia japonica.

Luehdorfia japonica Leech (Papilionidae, tribe Zerynthiini) is a swallowtail butterfly whose larvae feed exclusively on the plant genus Heterotropa (Aristolochiaceae). Luehdorfia japonica females were strongly stimulated to lay eggs on filter paper treated with a methanolic extract of the host plant leaves. The oviposition stimulant factor was composed of several water-soluble components. One of the oviposition stimulants was isolated from the leaves of Heterotropa aspera and identified as isorhamnetin 3-O-glucosyl-(1-->6)-galactoside-7-O-glucoside. This compound was inactive alone but induced the specific oviposition response from L. japonica females when tested as a mixture with other unidentified components.