千葉県南房総市高塚山におけるアサギマダラの発生経過

抄録

This study was performed to investigate the seasonal variations in the emergence of the Chestnut Tiger Butterfly (Parantica sita niphonica) in a Marsdenia tomentosa population on Mt. Takatsuka in Minamiboso-City, Chiba Prefecture, Japan, between February 2006 and April 2015. There were two main periods of emergence per year: the overwintering generation, in which eggs were laid from mid-October to mid-December, with the larvae growing until April of the following year; and the first generation for which eggs were laid from early May to late June, with the larvae growing until early July. In some years, a second generation occurred between the first and overwintering generations. These results were compared with those of previous studies conducted in Kanagawa Prefecture and the northern Kanto region. In Kanagawa Prefecture, the overwintering generation and the first and second generations were confirmed, as in Chiba Prefecture, while the second generation was found infrequently in northern Kanto region. The growth of M. tomentosa on Mt. Takatsuka was investigated simultaneously with the larval survey. The tops of these plants on Mt. Takatsuka withered in summer. Neither flowering nor fruiting was observed on Mt. Takatsuka.