The first DNA barcode library of Chironomidae from the Tibetan Plateau with an evaluation of the status of the public databases

Abstract

The main aim of this study was to curate a COI barcode library of Chironomidae from the Tibetan Plateau (TP) as an essential supplement to the public database. Another aim is to evaluate the current status of the public database of Chironomidae in aspects of taxonomic coverage, geographic representation, barcode quality, and efficiency for molecular identification, the Tibetan Plateau, China. In this study, 512 individuals of Chironomidae from the TP were identified based on morphological taxonomy and barcode analysis. The metadata of public records of Chironomidae were downloaded from the BOLD, and the quality of the public barcodes was ranked using the BAGS program. The reliability of the public library for molecular identification was evaluated with the newly curated library using the BLAST method. The newly curated library comprised 159 barcode species of 54 genera, of which 58.4% of species were likely new to science. There were great gaps in the taxonomic coverage and geographic representation in the public database, and only 29.18% of barcodes were identified at the species level. The quality of the public database was of concern, with only 20% of species being determined as concordant between BINs and morphological species. The accuracy of molecular identification using the public database was poor, and about 50% of matched barcodes could be correctly identified at the species level at the identity threshold of 97%. Based on these data, some recommendations are included here for improving barcoding studies on Chironomidae. The species richness of Chironomidae from the TP is much higher than ever recorded. Barcodes from more taxonomic groups and geographic regions are urgently needed to fill the great gap in the current public database of Chironomidae. Users should take caution when public databases are adopted as reference libraries for the taxonomic assignment.

The mystery of distribution of Smittia brevipennis (Diptera, Chironomidae, Orthocladiinae)

“…Gadawski et al, 2022) while the same values for the orthoclads of the Tibetan plateau (2.5 mln km 2 ) are 2.13%(Han et al, 2023). The complete absence of any mutations in the gene COI of S. brevipennis from the islands and mainland coast of the Arctic Ocean (area of the Arctic Ocean more than 14 mln km 2 ) indicates a relatively recent and rapid formation of the area compared to other orthoclads.…”

New descriptions of the larval and pupal stages of Orthocladius nitidoscutellatus and Psectrocladius nevalis from Xizang, China (Diptera, Chironomidae)

“…Since the first report of the male adults of Psectrocladius nevalis Akhrorov, 1977 in Lake Zorkul on the Pamir Plateau in Tajikistan, there has been little research related to this species ( Akhrorov 1977 , Ashe and O'Connor 2012 ). To date, only simple descriptions of male adults of this species and public data about its barcode by Chinese scholars are available ( Han et al 2023 ).…”

DNA barcodes and morphology reveal new species within the Rheotanytarsus guineensis species group from China (Diptera: Chironomidae)

“…The DNA barcode, corresponding to the 658‐bp fragment of the 5′‐end of the mitochondrial gene cytochrome c oxidase I (COI), has been identified as the core of a global bio‐identification system at the species level and it has been considered the most commonly used marker for identifying nonbiting midge species delimitation (Hebert, Cywinska, et al, 2003; Hebert, Ratnasingham, et al, 2003). COI barcodes have provided important evidence to confirm new species (Anderson et al, 2013; Ekrem et al, 2018; Gadawski et al, 2022; Han et al, 2020, 2023; Kodama et al, 2018; Lin et al, 2015, 2018, 2019, 2020; Lin, Jiang, et al, 2021; Lin, Mo, et al, 2021; Lin et al, 2021; Song et al, 2018; Stur et al, 2019). In the R. guineensis group, DNA barcodes for only one species ( Rheotanytarsus ringei Lehmann, 1970) were reported in past studies.…”