title: Molecular assessment of predation by hoverflies (Diptera: Syrphidae) in Mediterranean lettuce crops.
abstract: BACKGROUND
  Hoverflies (Diptera: Syrphidae) are generalist predators of a great variety of pests. Nasonovia ribisnigri (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g., Collembola). A semi-field experiment was conducted in an experimental lettuce plot where hoverfly predation on N. ribisnigri, F. occidentalis and Collembola was studied by conventional PCR and qPCR using specific primers, as well as by next-generation sequencing (NGS) in order to reveal other potential trophic interactions.
  
  
  RESULTS
  Trophic linkages between hoverflies and N. ribisnigri were the strongest both in spring and summer. F. occidentalis and Collembolans were also detected in both seasons, but with less frequency. qPCR detected a higher frequency of consumption than conventional PCR when both tests were run at optimal conditions. NGS analyses showed intraguild predation on other hoverfly species, as well as on anthocorids, spiders and even aphid parasitoids.
  
  
  CONCLUSIONS
  Conventional PCR and qPCR provided important insights into Mediterranean hoverfly species predation on target pest and non-pest prey. NGS gave a complementary approach revealing a broader diet of these predators within the studied ecosystem.
authors.affiliation: Entomology, Institute for Research and Technology in Food and Agriculture (IRTA), Cabrils, Barcelona, Spain.
authors.forename: Priscila
authors.initials: P
authors.lastname: Gomez-Polo
authors.affiliation: Entomology, Institute for Research and Technology in Food and Agriculture (IRTA), Cabrils, Barcelona, Spain.
authors.forename: Oscar
authors.initials: O
authors.lastname: Alomar
authors.affiliation: Entomology, Institute for Research and Technology in Food and Agriculture (IRTA), Cabrils, Barcelona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Castañé
authors.affiliation: United States Department of Agriculture, Agricultural Research Service (USDA-ARS), North Central Agricultural Research Laboratory, Brookings, SD 57006, USA.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Lundgren
authors.affiliation: Universitat Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, Spain.|Centre for Research on Ecology and Forestry Applications (CREAF), Cerdanyola del Vallès, Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Piñol
authors.affiliation: Entomology, Institute for Research and Technology in Food and Agriculture (IRTA), Cabrils, Barcelona, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Agustí
mesh_terms: D000818:Animals; D004175:Diptera / Q000502:physiology*; D020387:Food Chain; D005766:Gastrointestinal Contents; D007313:Insecta / Q000502:physiology*; D018545:Lactuca / Q000469:parasitology; D016133:Polymerase Chain Reaction; D011235:Predatory Behavior; D012621:Seasons; D017422:Sequence Analysis, DNA; D013112:Spiders
keywords: conventional PCR; gut content analysis; hoverflies; next-generation sequencing; polyphagous predators; qPCR