The tigerfly (or "hunter fly") Coenosia attenuata Stein (Diptera: Muscidae: Coenosiini) is a generalist predator that preys on several pests of greenhouse crops and is considered a biological control agent in the Mediterranean region. Previous behavioral observations identified its preferred prey, but a more in-depth evaluation will benefit from using Polymerase Chain Reaction amplification of prey DNA remains in the gut of this predator.
To evaluate the rate of decay and suitability of this method for use in the field assessments, a laboratory feeding calibration experiment was carried out on 355 females of C. attenuata, which were killed at different intervals of time after ingestion (10 time points from 0 to 48 h). The prey species tested were: Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae: Trialeurodini), Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), Diglyphus isaea
(Walker) (Hymenoptera: Eulophidae: Cirrospilini), Bradysia impatiens (Johannsen) (Diptera: Sciaridae), and Drosophila merca-
torum Patterson & Wheeler (Diptera: Drosophilidae: Drosophilini).
Based on a probit model, amplification success of prey DNA declined exponentially with increasing time after ingestion. The half-time molecular detection differed between species, ranging from an average of 5 h for T. vaporariorum and D. isaea, 6 h for B. impatiens, 15 h for L. huidobrensis to more than 40 h for D. mercatorum. This study confirmed the feasibility of using DNA-based detection to identify prey species in the gut contents of C. attenuata and provided calibration curves for a better understanding of predation activity in this agroecosystem
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Seabra, Sofia & Martins, Joana & Brás, Patrícia & Tavares, Ana & Freitas, Inês & Barata, António & Rebelo, Maria Teresa & Mateus, C. & Paulo, Octávio & Figueiredo, Elisabete. (2021). PCR-based prey DNA detection in the gut content of the tiger-fly, Coenosia attenuata (Diptera: Muscidae), a biological control agent in Mediterranean greenhouses. European Journal of Entomology. 118. 335-343. 10.14411/eje.2021.035.