Monitoring insect biodiversity and comparison of sampling strategies using metabarcoding: A case study in the Yanshan Mountains, China

Abstract

Insects are the richest and most diverse group of animals and yet there remains a lack, not only of systematic research into their distribution across some key regions of the planet, but of standardized sampling strategies for their study. The Yanshan Mountains, being the boundary range between the Inner Mongolian Plateau and the North China Plain, present an indispensable piece of the insect biodiversity puzzle: both requiring systematic study and offering opportunities for the development of standardized methodologies. This is the first use of DNA metabarcoding to survey the insect biodiversity of the Yanshan Mountains. The study focuses on differences of community composition among samples collected via different methods and from different habitat types. In total, 74 bulk samples were collected from five habitat types (scrubland, woodland, wetland, farmland and grassland) using three collection methods (sweep netting, Malaise traps and light traps). After DNA extraction, PCR amplification, sequencing and diversity analysis were performed, a total of 7427 Operational Taxonomic Units (OTUs) at ≥97% sequence similarity level were delimited, of which 7083 OTUs were identified as belonging to Insecta. Orthoptera, Diptera, Coleoptera and Hemiptera were found to be the dominant orders according to community composition analysis. Nonmetric multidimensional scaling (NMDS) analysis based on Bray–Curtis distances revealed highly divergent estimates of insect community composition among samples differentiated by the collection method (R = .524802, p = .001), but nonsignificant difference among samples differentiated according to habitat (R = .051102, p = .078). The study therefore appears to indicate that the concurrent use of varied collection methods is essential to the accurate monitoring of insect biodiversity.

Metabarcoding advances agricultural invertebrate biomonitoring by enhancing resolution, increasing throughput, and facilitating network inference

“…Studies have also combined malaise traps with metabarcoding to assess changes in species richness in conservation areas (Köthe et al, 2023), biodiversity in restored environments (Lynggaard et al, 2020) and temporal changes in invertebrates across agricultural (Hausmann et al, 2022) and forest landscapes (Kirse et al, 2021), and to create species inventories (Li et al, 2023). Due to the design of the trap, specimens are immediately stored in a suitable preservative, such as a high purity ethanol (deWaard et al, 2019;Kirse et al, 2021;Swenson et al, 2022), requiring no modifications.…”

“…Nets are a common tool for entomological surveys and different types of net have been used in combination with metabarcoding to investigate insect-plant trophic interactions (Foster et al, 2020), and biomonitoring (Pentinsaari et al, 2020;Svenningsen et al, 2021;Li et al, 2023). Furthermore, in a study by Svenningsen et al (2021), nets attached to the roof of cars were used to sample flying insects in Denmark.…”

“…Details on practices to reduce contamination between samples collected using the same net are lacking, which is an important consideration for metabarcoding studies (Harwood, 2008). There are multiple studies which either omit this information, or do not consider cross-contamination (Foster et al, 2020;Li et al, 2023). We recommend studies implement measures such as decontaminating nets between sampling, or using different nets for each sample.…”

Overcoming life stage‐centric biases illuminates arthropod diversity, systematics and biology

“…The emphasis in systematics on one semaphoront has limited, whether by design or by necessity, biodiversity inventory efforts to focusing preferentially on the most identifiable specimens, ignoring or regarding others as uninformative, or as an unavoidable nuisance (Domènech et al, 2022). For instance, in insects, the most widely publicized data associated with reports of overall declines have been entirely based on flying (therefore adult) insects collected by light and Malaise traps (Hallmann et al, 2017;Lister & Garcia, 2018;Mata et al, 2021), and many more general inventory attempts focus mainly on flight-trapped insects, mostly excluding other semaphoronts (Chimeno et al, 2023;Kaczmarek et al, 2022;Li et al, 2023;Montgomery et al, 2021;Srivathsan et al, 2023;Steinke et al, 2021). However, many of the critical life-history niches occupied by insects are populated by their immature stages, the portion of life during which most of their growth and development occurs, and this is equally true, if less well-appreciated, in other arthropod groups (e.g., oribatid mites; Norton & Ermilov, 2014).…”

Upscaling biodiversity monitoring: Metabarcoding estimates 31,846 insect species from Malaise traps across Germany

“…DNA metabarcoding analyses to date have been limited to either a specific region within a country (e.g., Geiger et al 2016, Uhler et al 2021, Habel et al 2023), short time spans (e.g., Huang et al 2022, Li et al 2023) or specific taxonomic groups (e.g., Chimeno et al 2022, Huang et al 2022). None has quantified the full extent of insect diversity – including dark taxa – at the whole-country scale and through time.…”