Enhancing the dung beetle iDNA tool for mammalian biodiversity monitoring and ecological studies 优化粪甲虫iDNA技术，用于哺乳动物多样性监测和生态学研究

Many species of dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are coprophages and possess trophic connections with mammalian dung. Recent studies have shown that the use of genetic information from dung beetle guts (invertebrate-derived DNA or iDNA) allows for the detection of mammals in a given habitat without intensively surveying the area. However, these studies used live or freshly killed beetles instead of preserved specimens. Here, we assessed the feasibility of extracting and sequencing iDNA from dung beetles that were collected using conventional baited pitfall traps with a mixture of propylene glycol and ethanol. We extracted iDNA from the guts of 18 dung beetles, comprising three species and three functional groups, collected from a seasonal tropical forest in Xishuangbanna, China. Eight mammalian species were detected, including rare species not previously recorded at the same location. Among the three functional groups, paracoprids (tunnelers) yielded the highest number of mammal species. Our study shows that iDNA can be successfully sequenced from preserved specimens, provided they are stored under appropriate conditions. The proposed technique offers a viable alternative to traditional cafeteria experiments for understanding dung beetle-mammal interactions and can serve as a valuable complementary approach to current mammal survey techniques.