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

Abstract

A B S T R A C TThe codling moth Cydia pomonella L. (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 detect C. pomonella prey in the diets of birds occupying organic apple orchards. We tested published Tortricidae primers, polymerase chain reaction (PCR) and sequencing for detection of C. pomonella in 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 of C. pomonella in the laboratory and from field samples. C. pomonella DNA was amplified in less than 1% of field samples and was successfully sequenced in 0.5%. A single species, the brown-headed cowbird Molothrus ater (Boddaert), had fecal samples positive for C. pomonella DNA. While our results do not provide evidence that birds play a strong role in the control of C. pomonella in 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.

Identifying Molecular-Based Trophic Interactions as a Resource for Advanced Integrated Pest Management

“…Commonly in vertebrate systems, fecal samples or pellets are collected for DNA analysis either by trapping individual birds or bats within the crop system of interest, or by passively collecting fecal pellets from bat roosting sites. The analysis of vertebrate pest consumption ranges from targeted single prey species [ 63 , 64 ] to DNA metabarcoding analysis that captures diet breadth [ 65 , 66 , 67 ], as well as the targeted sampling of a single predator [ 68 , 69 , 70 , 71 ] or multiple predator species or communities. Although more research is warranted, some general patterns of vertebrate pest consumption have emerged, including evidence of density-dependent foraging by birds and bats, as well as evidence of both services and disservices.…”

Landscape drivers and effectiveness of pest control by insectivorous birds in a landscape-dominant woody crop

“…Unfortunately, there is a notable gap in studies analyzing bird insectivore diet in olive groves in relation to its major pests, whereby there is no information of reference. As done in other agroecosystems (e.g., Karp et al 2013 in coffee plantations or Mangan et al 2018 in apple orchards), studies analyzing bird diet with molecular tools (e.g. DNA analyses form faecal sampling) are needed to elucidate how frequently insectivorous birds feed on olive pests.…”

Tradeoffs of using place‐based community science for urban biodiversity monitoring

“…Species were categorized as human‐sensitive or human‐adapted based on how they were classified in previous studies (Supporting Information Table S2). Because classifications are both context specific, we used classifications from studies in similar geographic areas and residential settings when available (Farr, Pejchar, & Reed, 2017; Mangan, Piaggio, Hopken, Werner, & Pejchar, 2018; Odell et al, 2007).…”