抄録
To examine the relationships between the northward distributional expansion of the great mormon butterfly, Papilio memnon Linnaeus, and climatic warming in Japan, we analyzed a data set on temperatures near the northern range limit of the species for the past ca 60 years from the year 1940 until 1998. Within the distributional range of the species in southwestern Japan in the year 2000, a significant increase in temperature (i.e., climatic warming) occurred and a significant increase in the latitude of the northern range margins was detected during the period analyzed. That is, the latitude of northern range margins in the species increased with the increasing mean temperature of the coldest month and annual mean temperature in southwestern Japan. Thus, it is suggested that climatic warming as a major external factor may have played an important role in its northward expansion. The averages of annual mean temperatures and mean temperatures of the coldest month near the northern range margins were 15.46℃ and 4.51℃, respectively. Our analysis also suggested that there were different types of northward range expansion patterns of the species. We discuss the patterns mainly from the point of external factors.
