2025 Volume 24 Issue 2 Pages 151-170
As a preliminary investigation to elucidate the impact of Pallas's squirrel on insect populations, we conducted an insect capture survey using traps in the forests of a small island (Takashima, Oita City, Kyushu, Japan) before squirrel eradication, as well as on the squirrel-free peninsula (Saganoseki) on the opposite shore. Three types of baited traps were employed: flight intercept traps, pitfall traps, and hornet traps. At the insect group level, species richness and abundances for longhorn beetles and hornets were significantly higher on the peninsula, likely due to negative effects of squirrel predation. In contrast, the abundance of necrophagous silphid and dung beetles was significantly higher on the island, presumably reflecting the high availability of squirrel carcasses. No significant differences were observed in ground beetles, suggesting they were unaffected by squirrel presence. The findings of this study can be utilized in post-eradication comparative research to assess the impact of the squirrel.
