PCR-based gut content analysis to identify arthropod predators of Haplodiplosis marginata

Abstract

Saddle gall midge (Haplodiplosis marginata) is a cereal pest exhibiting sporadic outbreaks for which chemical control options are limited. Integrated Pest Management programs may offer a means of suppressing H. marginata outbreaks, reducing pesticide input. Many IPM programs benefit from the natural population suppression inflicted through predation and parasitism. The larval stage of H. marginata overwinters in the soil and may be preyed upon by ground-dwelling arthropods, however the natural enemies of H. marginata remain unrecognized. A PCR-based assay for detecting H. marginata in the guts of predators was designed using novel species-specific primers. Feeding trials involving H. marginata larvae showed a detectability half-life of 31.07 hours post-feeding in Nebria brevicollis. The guts of field-caught Carabidae were screened for H. marginata DNA. Four species: Poecilus 2 versicolor, Nebria brevicollis, Harpalus rufipes and Loricera pilicornis were identified as natural enemies of H. marginata for the first time. A higher proportion of positive results were obtained at the end of H. marginata emergence (July) compared to the beginning (May). The importance of understanding trophic interactions in the management of H. marginata is discussed in addition to the potential uses for the newly designed assay and primers.

PCR Species-Specific Primers for Molecular Gut Content Analysis to Determine the Contribution of Generalist Predators to the Biological Control of the Vector of Xylella fastidiosa

“…Both primer pairs were very sensitive given that P. spumarius DNA was amplified in all the heterospecific DNA mixes, even when potential predator DNA was in great excess (Ratio 1:4000) (Figure 4). Outcomes returned a detection limit of 2.5 pg/µL of P. spumarius DNA, surpassing that obtained for the same gene on sharpshooters (6 pg/µL [34]), equaling the one obtained for Haplodiplosis marginata [35] and slightly higher than that for the olive pest, Bactrocera oleae (1 pg/µL [26]). phylogeny and DNA barcoding of P. spumarius and its related species is found in the literature [14].…”

Biological and ecological features of xylem-feeder vectors through establishment of a sustainable strategy for control of "Xylella fastidiosa"-vectors

“…These primer pairs target regions from two mitochondrial protein-coding genes, i.e., the standard barcode for invertebrates, cytochrome c oxidase subunit I (COI_Ph71F/COI_Ph941R), and the cytochrome b (cytB_Ph85F/cytB_Ph635R) genes. Currently, the COI gene is one of the most used markers for PCR-based gut-content analysis in arthropods (Monzó et al, 2010;Sint et al, 2011;Rejili et al, 2016;Unruh et al, 2016;Rowley et al, 2017;Macías-Hernández et al, 2018), including for the detection of Philaenus (Lantero et al, 2018).…”