About Papilio xuthus Linnaeus, 1767
Papilio xuthus Linnaeus, 1767, commonly called the Asian swallowtail, is a mid-sized, yellow butterfly with prominent tail projections on its wings. Its wingspan ranges from 90 to 110 mm. Its typical color pattern is made up of black markings on a yellow background. Wing coloration is sexually dimorphic: females have broader proximal marginal bands on the hindwing. Iridescent blue and orange scales separate the black bands on the hindwing, and black bands also form stripes of varying thickness along the forewing. Young caterpillars of this species mimic bird feces, and have a white and brown spot on their heads. As caterpillars mature, they develop a light green body with brown spots. Aside from predation, larval mortality is also affected by diseases that appear to correlate with the length of the rainy season. Long periods of rain in autumn cause rotting in infected larvae. The larvae of this species feed on plants in the family Rutaceae. Recorded food plant species include: Phellodendron amurense, Poncirus trifoliata, Zanthoxylum species such as the Japanese pepper tree (Z. piperitum), Z. nitidum, and Japanese prickly-ash (Z. ailanthoides), cultivated Citrus species such as mandarin orange and yuzu, Euodia ruaecarpa, Ruta graveolens (rue), and "Bauhinia" species such as the Hong Kong Orchid Tree.
