A comparative analysis of spider prey spectra analyzed through the next‐generation sequencing of individual and mixed DNA samples

Abstract

As one of the most abundant predators of insects in terrestrial ecosystems, spiders have long received much attention from agricultural scientists and ecologists. Do spiders have a certain controlling effect on the main insect pests of concern in farmland ecosystems? Answering this question requires us to fully understand the prey spectrum of spiders. Next-generation sequencing (NGS) has been successfully employed to analyze spider prey spectra. However, the high sequencing costs make it difficult to analyze the prey spectrum of various spider species with large samples in a given farmland ecosystem. We performed a comparative analysis of the prey spectra of Ovia alboannulata (Araneae, Lycosidae) using NGS with individual and mixed DNA samples to demonstrate which treatment was better for determining the spider prey spectra in the field. We collected spider individuals from tea plantations, and two treatments were then carried out: (1) The DNA was extracted from the spiders individually and then sequenced separately (DESISS) and (2) the DNA was extracted from the spiders individually and then mixed and sequenced (DESIMS). The results showed that the number of prey families obtained by the DESISS treatment was approximately twice that obtained by the DESIMS treatment. Therefore, the DESIMS treatment greatly underestimated the prey composition of the spiders, although its sequencing costs were obviously lower. However, the relative abundance of prey sequences detected in the two treatments was slightly different only at the family level.Therefore, we concluded that if our purpose were to obtain the most accurate prey spectrum of the spiders, the DESISS treatment would be the best choice. However, if our purpose were to obtain only the relative abundance of prey sequences of the spiders, the DESIMS treatment would also be an option. The present study provides an important reference for choosing applicable methods to analyze the prey spectra and food web compositions of animal in ecosystems.

Field investigation‐ and dietary metabarcoding‐based screening of arthropods that prey on primary tea pests

“…However, the life stage of prey cannot be identified by the present method because the primers were not specific to any life stage (Yang, Liu, Yuan, Zhang, Peng, et al, 2017). Similar to the results of Yang et al (2021), a few spider species ( Neoleptoneta sp., Pardosa sp., and Theridion sp. ; Table ) were included in the prey spectrum of C. blandum , thus indicating intraguild predation (Michalko et al, 2021).…”

“…Universal primer pairs (mlCOIintF/Fol‐degen‐rev) can amplify the COI gene in the prey remains within the spider's gut as well as in the spider itself. Similar to the results of Piñol et al (2014) and Yang et al (2021), the sequence annotation showed that most of the sequences belonged to the predator itself, which accounted for 90.9% of the total sequences. In addition, nonprey sequences (including fungi, Chordata, aquatic taxa (Cnidaria, Rotifera, Bacillariophyta, Phaeophyta, Rhodophyta, and some aquatic arthropods) and soil‐dwelling taxa (Annelida)) were found in the sequencing results, which accounted for 1.6% of the total sequences.…”

“…Similar to the results ofYang et al (2021), a few spider species (Neoleptoneta sp., Pardosa sp., and Theridion sp. ; TableS6) were included in the prey spectrum of C. blandum, thus indicating intraguild predation(Michalko et al, 2021).…”

“…; Table ) were included in the prey spectrum of C. blandum , thus indicating intraguild predation (Michalko et al, 2021). Intraguild predation is a common phenomenon observed in diet analyses of spiders (Saqib et al, 2021; Yang et al, 2021), and it is likely an adaptive strategy that helps spiders address energy limitations caused by scarce prey (Haghani et al, 2019; Michalko et al, 2021; Wise, 1995). Among the prey species, most included tea pests, and the three main tea pest species were found in the prey spectrum of C. blandum (Table ).…”

“…For the first two questions, field investigations can be performed to determine the dominance of predators and temporal and spatial dynamic relationships between predators and pests (Dang et al, 2010; Ye et al, 2010). For the last question, a predator diet analysis can be performed to determine the prey composition of predators (Yang et al, 2021). In tea plantation ecosystems, the control of predators on tea pests is mostly evaluated based on the dominance of predators and temporal and spatial dynamic relationships between predators and pests.…”