New Publication: Using Metabarcoding Techniques to Map Multiple Dung Beetle-Vertebrate iDNA Networks in a Southeast Asian ForesT

Species interact with each other through complex ecological networks. The structure of these networks can be altered by anthropogenic drivers, such as agricultural expansion and climate change, which may impact ecosystem functioning. Increasingly, molecular techniques are being used to monitor biodiversity and construct ecological networks, circumventing the constraints associated with using conventional means to document species interactions over time and space.

Field surveys and molecular lab procedures to detect vertebrate DNA from dung beetle gut contents. Photos 2026 Marx Yim.

In our recent publication in Molecular Ecology Resources, we present an optimised DNA metabarcoding protocol to detect vertebrate DNA from the gut contents of dung beetles. We then used this technique to construct quantitative dung beetle-vertebrate trophic networks across a wide spatial area.

Before constructing interaction networks, it is important to determine how long vertebrate DNA remains detectable from dung beetle gut contents after a feeding event. Through a feeding experiment, we found that the highest probability of detecting vertebrate DNA from dung beetle gut contents is within 3 h of feeding. Interestingly, vertebrate DNA can still be detected in most beetles after 24 h, including around 50% of beetles with visually empty guts.

Dung beetles with full guts have the highest DNA amount while DNA was still detectable in some individuals with visually empty guts. Source: Ong et al. 2026.

Based on these findings, we used our optimised protocol to detect vertebrate DNA from the gut contents of dung beetles sampled from ground and canopy traps deployed across 50 forest sites in Singapore's Central Catchment Nature Reserve. By using group-specific primers, we documented interactions between dung beetles and multiple vertebrate species, including amphibians, birds, and rare mammals, such as the Sunda slow loris and Sunda pangolin.

Overall canopy and ground networks showing direct interactions between dung beetle and vertebrate species. Source: Ong et al. 2026.

Across the 50 sites, we constructed 32 site-level (i.e., combined canopy and ground) quantitative dung beetle-vertebrate trophic networks, which were generally similar in structure and displayed high trophic generalism and nestedness.

32 site-level networks arranged based on the number of detected vertebrate species in each site. Source: Ong et al. 2026.

Our study demonstrates the effectiveness of molecular approaches in constructing and monitoring multiple ecological networks across large spatial scales, providing high-resolution insights into individual dung beetle–vertebrate interactions. These techniques contribute towards the development of new methods for comprehensive biodiversity assessments and ecological network studies that are urgently needed for hyper-diverse yet understudied locations that are undergoing rapid environmental change.

Find out more about our study through this Video Abstract. The paper is published as open-access at: https://onlinelibrary.wiley.com/doi/10.1111/1755-0998.70151