Abstract
The photoperiodic response curve for pupal diapause induction of the butterfly Atrophaneura alcinous was determined in several temperate and subtropical populations of the Japan Archipelago at 20°C, using Aristolocia debilis leaves as larval food. Altitude and host plant use also differed among them. For the temperate populations of Kiire, Kashihara, Fuchu, Yokosuka and Yamagata, the critical photoperiod increased with latitude, and the subtropical Ishigaki population showed the shortest critical photoperiod. Further, a change in the shape of photoperiodic response curve, but no shift in the critical photoperiod, was found in a mountain population of Kiire, giving a high incidence of diapause in long photoperiods. These results are discussed in relation to latitude, altitude, and host plant.
