A molecular analysis to assess codling moth Cydiapomonella L. (Lepidoptera: Tortricidae) predation by orchard birds

摘要

The codling mothCydia pomonellaL. (Lepidoptera: Tortricidae) is a major economic pest in organic apple orchards. Observational methods, prey removal experiments and correlative experiments with exclosures or nest boxes have demonstrated that birds contribute to the removal of this insect pest. However, the majority of research conducted in the last several decades has taken place outside of the United States and methods for studying biological pest control have advanced dramatically and now include molecular techniques. We conducted a proof-of-concept study to test a DNA-based approach to detectC. pomonellaprey in the diets of birds occupying organic apple orchards. We tested published Tortricidae primers, polymerase chain reaction (PCR) and sequencing for detection ofC. pomonellain avian feces. We also tested the quality of DNA isolated and purified from fecal samples using two DNA extraction kits. Finally, we field-tested this tool to identify the presence or absence ofC. pomonellain the laboratory and from field samples.C. pomonellaDNA was amplified in less than 1% of field samples and was successfully sequenced in 0.5%. A single species, the brown-headed cowbirdMolothrus ater(Boddaert), had fecal samples positive forC. pomonellaDNA. While our results do not provide evidence that birds play a strong role in the control ofC. pomonellain western Colorado organic apple orchards, the approach we present is a new tool for understanding bird-mediated ecosystem services, avian feeding ecology, and supporting management decisions for sustainable agricultural practices and farmland biodiversity.