Chemical composition of volatile substances from adults of the swallowtail, Papilio polytes (Lepidoptera:Papilionidae)

Adults of the swallowtail butterfly Papilio polytes have a faint scent, which is stronger in males than in females. From the solvent extracts from adults, six relatively high-volatile substances including linalool, nonanal, and decanal were detected in small amounts. Since males contained more linalool than females in the average amount per individual, this compound is believed to be attributable the male's strong scent. The majority of the substances is somewhat concentrated on the wings rather than on the body, whereas acetoin is mainly present in the body, particularly in the thorax for both sexes. In addition, the solvent extracts were found to have large amounts of relatively low-volatile substances in which six n-alkanes, three n-alkenes, and four carboxylic acids possessing 10 to 29 carbon numbers were identified, and the major components were n-heptacosane, n-nonacosane, and hexadecanoic acid. In the extracts from individual whole 3-d-old adults, (Z)-7-tricosene and dodecanoic acid were significantly more abundant in males than in females, while (Z)-7-pentacosene and n-heptacosane were significantly more abundant in females than in males, indicating that the swallowtail adults have a sexual dimorphism in volatile composition. During the 3 d after emergence, most of the identified components averagely increased by twice the amount per adult.