Lack of maintenance of the forest floor have increased abandoned Satoyama areas. Abandonment Satoyama influence not only number of plants but also insects. This study investigated reason of few numbers of C. insulicola at bamboo forest by looking at the condition of soil surface hardness by field surveys and room experiments. Firstly, we checked and classified by cluster analysis the relationships of vegetation types and numbers of C. insulicola populations by field surveys. The vegetation type survey was made in an abandoned forest floor and bamboo forest area by cutting mainly Pleioblastus chino and Phyllostachys edulis. Secondly, the soil surface hardness was measured in each vegetation types for three years. Thirdly, room experiments were done to see whether C. insulicola can or cannot dig under different soil surface hardness in all year round. The results showed that few numbers of C. insulicola at bamboo forest were influenced by soil surface hardness, because the soil surface hardness was higher at the bamboo forest than at the abandoned forest. In the experiments, C. insulicola were not able to dig and hibernate under soil surface hardness, 2kg/cm2 in winter season.
