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Understanding biological control function and trophic interaction dynamics of an artificially released predatory bug
Weidong Huang1, Suyi Chen1, Zihua Zhao1
1State Key Laboratory of Agricultural and Forestry Biosecurity, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, 100193, China.
Insect Science
|May 26, 2025
Summary
This study reveals the diet of the assassin bug Sycanus bifidus in citrus orchards. Metabarcoding identified Lepidoptera as a major prey, highlighting S. bifidus
Area of Science:
- Agroecosystem ecology
- Biological pest control
- Molecular ecology
Background:
- Integrated pest management (IPM) relies on understanding predator-prey dynamics in agroecosystems.
- Augmentation biological control involves releasing natural enemies, but their dietary breadth and impact on pest populations are often unclear.
- Sycanus bifidus, an assassin bug, is used in citrus orchards, necessitating research into its feeding habits.
Purpose of the Study:
- To determine the dietary composition of Sycanus bifidus in citrus agroecosystems.
- To reconstruct the trophic interactions of S. bifidus with various pest species.
- To evaluate the potential of S. bifidus as a biological control agent using molecular gut content analysis.
Main Methods:
- Molecular gut content analysis using metabarcoding was employed to identify prey DNA in S. bifidus samples.
- 30 prey taxa from 8 orders and 19 families were detected in 108 S. bifidus specimens collected over 22 days.
- Primer pair efficiency for degraded DNA detection was assessed, with the Fwh primer set identified as optimal.
Main Results:
- Lepidoptera constituted 30% of the S. bifidus diet, followed by Coleoptera, Hemiptera, and Hymenoptera.
- Euproctis varians, a significant citrus pest, was frequently detected, indicating its role as a key prey item.
- Metabarcoding successfully reconstructed trophic interactions and identified effective biological control agents.
Conclusions:
- Sycanus bifidus preys significantly on Lepidoptera, including the citrus pest Euproctis varians.
- This predator shows potential as an effective biological control agent for E. varians in citrus crops.
- Metabarcoding is a powerful tool for optimizing pest management strategies and understanding agroecosystem food webs.
