Comparison of Molecular and Conventional Methods for Estimating Parasitism Level in the Pomegranate Aphid Aphis punicae (Hemiptera: Aphididae)

Abstract

Aphidiinae (Braconidae: Aphidiinae) is a subfamily of endoparasitic wasps specialized in parasitizing aphids. Although, to date, different methods have been used to measure parasitism level, obtaining an accurate estimate remains challenging due to several limiting factors. This study was set to: 1) Compare efficiency of conventional and molecular-based methods in estimating parasitism level of the pomegranate aphid Aphis punicae (Passerini; Hemiptera: Aphididae), and 2) Estimate seasonal activity of the Aphidiinae parasitoids of the pomegranate aphid. The molecular approach (polymerase chain reaction [PCR]) detected the presence of three main parasitoids Lysiphlebus fabarum (Marshal; Hymenoptra: Braconidae), Binodoxys angelicae (Haliday; Hymenoptra: Braconidae), and Ephedrus persicae (Frogatt; Hymenoptra: Braconidae). The presence of hyperparasitoid and aphid DNAs did not interfere with the outcome, indicating specificity of the selected primers. Minimum concentrations of DNA needed for successful amplifications were 16.33, 28.65, and 22.65 ng µl−1, for L. fabarum, B. angelicae, and E. persicae, respectively. The level of parasitism was significantly higher in spring (28.42%) than both summer and fall; parasitism level during summer (11.89%) and fall (5.86%) formed a homogeneous statistical subset. Although the overall level of parasitism estimated by PCR (22.7%) was more than twofold higher than those estimated by a conventional counting method (10.5%), there was a strong positive correlation between the two approaches. Provided the potential limitations of either method, simultaneous use of both methods was recommended for an objective estimate of the effectiveness of the Aphidiinae parasitoids as biological control agents of A. punicae.

Early monitoring of parasitism by Aphidiinae parasitoids on the grain aphidSitobion miscanthiin wheat fields usingDNAbarcoding

“…The main advantages of the DNA barcoding technology include detecting immature parasitoids inside their aphid hosts and early, accurate, and effective monitoring of parasitism levels in aphids. 18,19,40 In the present study, we found that the COI barcode primers could efficiently amplify the target region from adult parasitic wasp samples as well as from S. miscanthi in mummified aphid and nonparasitized aphid samples. Thus, COI cannot be used for the unambiguous detection of immature parasitoids inside their S. avenae or S. miscanthi hosts.…”

A dearth of data: fitting parasitoids into ecological networks

“…It is important to follow good barcoding practices [50] to minimise the risk of finding nonpermissible interactions, or 'false positives', due to contamination. As such, we do not advocate the complete replacement of traditional rearing approaches with molecular techniques, rather that these approaches are complementary, and that rapid assessment with metabarcoding may serve as a useful indicator of where traditional rearing and morphological taxonomy efforts should be targeted [56]. In fact, the continued efforts of traditional taxonomists, particularly in the discovery and naming of species, rather than being devalued by the popularity of molecular approaches, should be considered essential for their successful application.…”

Applications of Biotechnology for Characterization of Plants and Pests as the Key Components of Plant Protection and Production Strategies: A Review

“…Accordingly, various molecular methods of characterization for microbes are extensively described in several review articles and books (Dickinson, 2005;Tsiamis et al 2014;Awasthi, 2015). The combined use of various conventional and molecular methods have been described mostly for the characterization of microorganism (Spiegelman et al, 2004;Martinelli et al, 2015;Cui et al 2018, Franco-Duarte et al, 2019 and insects (Farrokhzadeh et al, 2017).…”