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.

Marine biodiversity is rapidly declining due to anthropogenic activities; however, the key causal agents of this decline remain largely elusive. Improving our understanding of anthropogenic impact on biodiversity dynamics requires fine‐scale temporal observations, which are logistically challenging using traditional methods. Coral reef ecosystems are key biodiversity hotspots for a wide range of organisms, making them essential for wider marine ecosystem stability and important focal points for marine biodiversity dynamics research. The use of autonomous reef monitoring systems (ARMS) has been effective in assessing reef benthic biodiversity. However, it remains unknown how ARMS marine biodiversity changes over time or in response to anthropogenic activity. Here, we utilized eDNA and a full factorial experiment consisting of 12, 2,042 L mesocosms, seeded with ARMS previously colonized from natural reef habitats. A total of 240 eDNA samples were collected over 20 time points across 232 days to assess: (1) eDNA accumulation dynamics, (2) effects of anthropogenic activity on biodiversity dynamics and (3) eDNA degradation rates. Biological communities changed drastically over time, with 814 ASVs across 617 marine families identified over the course of the experiment. Arthropoda dominated during the accumulation phase, Mollusca during the treatment phase, and Platyhelminthes and Bacillariophyta during the degradation phase. Richness across all mesocosms increased to 110 ± 18 initially, then stabilized at 147 ± 31 during the treatment phase before declining rapidly to 49 ± 17 during the degradation phase. We found that fish feed had a significant negative effect on community composition over time (p < 0.01). Additionally, we identified Lithodesmiaceae and Haminoeidae as potential bioindicator groups. eDNA decay rates across species groups showed faster declines for fish compared to algae and invertebrates. Overall, our findings demonstrate that eDNA metabarcoding offers a detailed assessment of biodiversity, allowing us to differentiate between spatiotemporal and anthropogenic impacts on community dynamics.

The marine Chironomidae Ainuyusurika Sasa et Shirasaka, 1988, previously known from the adults only, is associated with its immature stages for the first time based on reared specimens from Oriental China. The larva resembles those of Sergentia Kieffer and Endochironomus Kieffer in the ventromental plate with an anteromedial projection and the 5-segmented antenna with opposite Lauterborn organs. The pupal thoracic horn has 12 branches at maximum and netted tergite spinulation which appears to be similar to those of Polypedilum Kieffer, Endotribelos Grodhaus, Phaenopsectra Kieffer and Sergentia. The phylogenetic relationship was furtherly explored through molecular analysis based on concatenation of five gene makers (18S, 28S, CAD1, CAD4 and COI-3P) using both mixed-model Bayesian and maximum likelihood inference methods. The result shows Ainuyusurika is nested with an assemblage of Endochironomus, Phaenopsectra and Endotribelos. We concluded that Ainuyusurika is a good independent genus showing affinity with Endochironomus-Phaenopsectra related genera.

Expanded generic diagnoses of all life stages of Yaeprimus Sasa et Suzuki, 2000 (Lunditendipes Harrison, 2000, syn. n.) are given. Yaeprimus tropicus comb. n. is redescribed as an adult based on type material. Additionally, a new species Y. balteatus sp. n. from Oriental China is described based on the adult male and pupa. The phylogenetic position of Yaeprimus within Chironomini and the validity of the new species are explored based on concatenated five genetic markers (18S, 28S, CAD1, CAD4, and COI-3P) through both mixed–model Bayesian inference and maximum likelihood methods. The results strongly support Yaeprimus as sister to Imparipecten Freeman, 1961, which counters a previously proposed systematical position based solely on morphology.

Kribiodosis Kieffer, 1921, an African genus of Chironomini (Diptera: Chironomidae), is newly recorded from the Oriental region through a new species K. cantonensis sp. n. Detailed descriptions of the male, female and a DNA barcode are provided. With the inclusion of the new species bearing scutal tubercle and fused tibial comb, the generic diagnosis needs revision and expansion. The phylogenetic position of Kribiodosis within the tribe Chironomini is explored based on five concatenated genetic makers (18S, 28S, CAD1, CAD4 and COI-3P) using both mixed-model Bayesian inference and maximum likelihood methods. Kribiodosis is placed as a core member of the Microtendipes group but its precise sister group remains unclear. Inclusion of the analysis of Nilodosis Kieffer, another Chironomini genus with an African-Oriental distribution, reveals an unexpected robust position as sister to a large and diverse inclusive group of many Chironomini.

Environmental DNA (eDNA) metabarcoding has transformed biodiversity monitoring across taxa from bacteria to mammals, yet sample collection remains a major bottleneck. Passive sampling via adsorption and entrapment has emerged as a promising alternative to overcome the limitations of conventional active filtration. However, the performance of passive sampling for microbial biodiversity monitoring remains unknown. Here, we developed passive sampling‐based microbial community profiling by testing five submersion times and three common eDNA extraction methods in mesocosms, and comprehensively evaluated it by comparing results with active filtration in estuarine and coastal environments. We found that passive sampling for 24 h with enzymatic extraction yielded significantly more eDNA and higher biodiversity than shorter durations and mechanical extractions. Passive sampling consistently outperformed active filtration at every field site, with average increases of >100% in eDNA yields and >50% in taxonomic and phylogenetic diversities. Additionally, active filtration and passive sampling yielded significantly different prokaryotic and microeukaryotic community compositions, driven primarily by turnover rather than nestedness (on average 4‐fold larger), implying that passive sampling is better suited for spatiotemporal detection than active filtration. Passive sampling showed greater sensitivity in identifying key environmental factors (3 vs. 2) and potential environmental bioindicators (40 vs. 20) compared with active filtration. Overall, this study establishes an efficient and practical passive sampling method for microbial biodiversity monitoring and environmental assessment in aquatic environments.