野生ニホンザルの糞に誘引されるセンチコガネ類について、日本の2つの温帯地域、金華山島（落葉樹林）と屋久島（照葉樹林）で調査し、センチコガネ類群集の季節的変動を明らかにした。428個のピットフォールトラップで金華山では1,682頭（2科5属9種）、屋久島では1,102頭（2科4属9種）の糞虫を捕獲した。その50％以上は小型（体長10mm未満）のトンネル屋タイプ（エンマコガネ属とコエンマコガネ属）であった。金華山は大型（体長10mm以上）のトンネル屋タイプ（オオセンチコガネ属とゴホンダイコクコガネ）が多く、屋久島は居住者タイプ（マグソコガネ属）が多く捕獲された。夏から秋の捕獲率は金華山90〜100％、屋久島：64〜95％で、捕獲率と捕獲数は他の季節より多かった。種によっては捕獲数が気温と正相関であったが、降雨量との関係はみられなかった。サル糞中種子を土中埋没する糞虫は、植物の初期段階における適応度に影響を与える可能性がある。

Media Summary

A study on dung beetles attracted to wild Japanese macaque feces in two temperate sites in Japan, Kinkazan and Yakushima, found temporal variations in the beetle community. Over 50% of captured beetles were small tunnelers, with large tunnelers common in Kinkazan and dwellers frequent in Yakushima. Capture rates were higher in summer and autumn at both sites, with temperature positively correlated with beetle numbers. Rainfall showed no significant relationship. Dung beetles burying seeds in macaque feces may impact plant fitness early on.

Abstract

Dung beetles attracted to the feces of wild Japanese macaques (Primates: Macaca fuscata Blyth) were studied at two temperate sites in Japan, Kinkazan (dominated by deciduous forest) and Yakushima (dominated by evergreen forest), to determine if temporal variations occur in the dung beetle community. Data from 428 pitfall traps baited with fresh Japanese macaque feces and placed during 15 sampling periods from 2015 to 2019 were analyzed. We captured 1,682 beetles (two families, five genera, and nine species) from Kinkazan and 1,102 beetles (two families, four genera, and nine species) from Yakushima. More than 50% of the beetles captured were small (body size < 10 mm) tunnelers (species of Onthophagus Latreille and Caccobius Thomson). Large (body size > 10 mm) tunnelers (species of Phelotrupes Jekel and Copris acutidens Motschulsky) were common in Kinkazan, and dwellers (species of Aphodius Illiger) were frequently obtained in Yakushima. At both sites, the capture rate and number of trapped beetles were greater during the summer and autumn (Kinkazan: 90–100%; Yakushima: 64–95%) than during other seasons. For several species, the number of beetles collected in each trap was positively correlated with mean temperature, but no relationship with rainfall was observed. From an ecological viewpoint, dung beetles burying seeds embedded in macaque feces might affect plant fitness in the initial stages.