2026/07/20 by Nikolas J. Willmott, Jack L. Scanlan, Mark J. Blacket +4 · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Environmental Science · #Environmental DNA in Biodiversity Studies #Genomics and Phylogenetic Studies #Insect symbiosis and bacterial influences
paper · pdf · doi:10.3897/mbmg.10.196568
openalex publication_date 2026/07/20 · openalex created_date 2026/07/21 · openalex updated_date 2026/07/25
Understanding insect predator–prey interactions is critical for crop protection, particularly within biological control and integrated pest management frameworks. Ladybeetles (Coleoptera, Coccinellidae) are widely used biocontrol predators of aphids (Hemiptera, Aphididae), which are among the most economically damaging pests of grains worldwide. However, post-release dietary assessment of ladybeetles remains challenging because of their polyphagous feeding behaviour. DNA metabarcoding provides a powerful molecular approach for resolving arthropod community composition and trophic interactions through simultaneous amplification and identification of multiple DNA fragments from mixed samples. Here, we applied a widely used insect surveillance metabarcoding workflow, modified through development and implementation of aphid-specific primers, to enhance targeted detection of aphid prey consumed by ladybeetles. We evaluated performance of this prey-targeted metabarcoding approach for dietary analysis and quantified aphid DNA detectability under controlled feeding and starvation regimes. We hypothesised that aphid DNA could be reliably recovered from whole ladybeetle samples using standard surveillance metabarcoding protocols, enabling detection of prey taxa present exclusively as gut contents, which may impact surveillance and diagnostics programs. Aphid DNA from multiple species was detected up to seventy-two hours post-ingestion and up to one hundred hours following cessation of ad libitum feeding, although detectability varied among aphid species and pre-feeding starvation treatments. These results demonstrate that prey-targeted metabarcoding increases sensitivity for dietary inference in predatory insects and provides a robust framework for detecting cryptic trophic interactions. Our findings further indicate that unintended prey detection may be common in arthropod metabarcoding datasets, with important implications for interpretation in biosurveillance and biosecurity monitoring.