Supplementary data from: Monitoring insect biodiversity and comparison of sampling strategies using metabarcoding: a case study in the Yanshan Mountains, China

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 7,427 Operational Taxonomic Units (OTUs) at ≥ 97% sequence similarity
level were delimited, of which, 7,083 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 collection method (R = 0.524802, p = 0.001), but
nonsignificant difference among samples differentiated according to
habitat (R = 0.051102, p = 0.078). The study therefore appears to indicate
that the concurrent use of varied collection methods is essential to the
accurate monitoring of insect biodiversity.