Mammalian DNA derived from invertebrates (iDNA), including blowfly iDNA, is an alternative tool to conventional camera trapping in assessing mammalian diversity. The method has been used in tropical mammal surveillance but no attempt has been made to compare the efficacy of blowfly iDNA and camera trapping for monitoring mammal diversity in subtropical forests. We compared the blowfly iDNA monitoring with camera trapping to assess mammal diversity in the subtropical Jiulongfeng Nature Reserve (JLF), China, over a one-month period. The camera traps captured 2508 animal photos of 11 species belonging to four orders, eight genera, and eight families, whereas the blowfly iDNA method successfully detected ten species from six orders, eight gener...