Metabarcoding, the combination of DNA taxonomy and high-throughput sequencing, is a promising tool for the rapid assessment and monitoring of biodiversity in mixed, bulk samples. The low representation of arthropods in biodiversity databases is due to the high cost (in terms of money, time and labor) associated with sorting and identifying samples from large-scale inventories. A cheap and efficient monitoring method will greatly help to address this impediment.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) investigated the utility of DNA metabarcoding in a study of patterns of litter arthropod diversity across land-use types in Xishuangbanna. They tested whether the MiSeq platform could be used effectively for arthropod metabarcoding in the tropics. They then asked whether clustered molecular operational taxonomic units (MOTUs) indicated significant community differentiation across land-use types and measured environmental gradients. Finally, they wanted to see which arthropod groups showed significant changes across land uses and deserved further attention.
 The researchers used a new primer combination targeting a 400 bp fragment of the COI gene and Illumina high-throughput sequencing to demonstrate the effectiveness of the Miseq platform for metabarcoding a wide variety of tropical arthropods. While this fragment was shorter than the regular barcode fragment (ca. 650 bp), it still allowed a perfect identification of the samples in the mock communities they simulated.
The researchers compared diversity and compositional differences between forests and plantations (rubber and tea) for all MOTUs and for eight arthropod groups. They detected finer patterns by assigning MOTUs to different classes and orders and analyzed diversity patterns for each order/class separately. The four land-use types had distinct arthropod communities, showing that each land-use class supported a unique arthropod assemblage. Ordination showed that rubber, tea and forest communities formed distinct clusters.  They found strong correlations between environmental gradients and species compositional changes across land-use types. Diversity (α-) was generally high in native tropical forests and lower in adjacent agricultural plantations, with greater changes detected between rubber and forest than between forest and tea. Turnover was higher in forests than plantations, but patterns differed among groups.
The researchers thus concluded that Metabarcoding was useful for quantifying diversity patterns of arthropods under different land uses and the MiSeq platform was effective for arthropod metabarcoding in the tropics.
The study entitled “The utility of DNA metabarcoding for studying the response of arthropod diversity and composition to land-use change in the tropics” has been published in Scientific Reports.

Contact
Kingsly Chuo Beng
Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: 1137179719@qq.com