Seasonal changes in native host plants of a migrant skipper, Parnara guttata Bremer & Grey (Lepidoptera: Hesperiidae).
In Japan, the rice pest (Parnara guttata) Bremer & Grey has 3 generations a year. The overintering larvae pupate in mid-May, and adults emerge in late May. The females oviposit on early planted rice, and the adults of the 1st generation emerge in mid-July. Larvae of the 2nd generation develop on mid-season rice and give rise to a large adult population in late August-early September. These adults migrate in large numbers, and the females lay their eggs on various kinds of grasses. The immature stages of the 1st and 2nd generations had never been recorded from plants other than rice. However, since rice is not native to Japan and knowledge of the indigenous food-plants of the hesperiid might lead to a better understanding of migration, a survey of food-plants other than rice was carried out in Kyoto in 1979-80. The results are given and discussed. Of the 16 plant species examined at the time 1st-generation larvae were developing, only early planted rice carried larvae. Of 8 species of grasses examined when 2nd-generation larvae were developing, larvae were found on Echinochloa crus-galli, Phragmites karka and Carex olivacea in addition to rice. Third-generation larvae were found on Imperata cylindrica, Miscanthus sinensis, Lolium perenne and Festuca ovina. During the studies, information was also obtained on the food-plant range of the closely related species Pelopidas mathias (F.).