The family Apataniidae consists of two subfamilies, Apataniinae and Moropsychinae. Currently, there are 204 valid species of Apataniidae, which are widely distributed throughout the northern hemisphere. The larvae typically inhabit cold-water environments, and they serve as biological indicators for monitoring the health of freshwater ecosystems. The phylogenetic relationships within Apataniidae are not fully understood. Moreover, the available molecular data of Apataniidae are still limited. Herein, we provided the mitochondrial genomes of eight apataniid species and compared them with the published mitochondrial genomes of Apataniidae. The nine newly obtained sequences ranged from 15,070 bp to 16,737 bp in length. The results of the nonsynonymous with synonymous substitution rates displayed that ATP8 had the highest evolutionary rate, while COXI exhibited the lowest. The ND4L may be an effective molecular marker for the classification of the Apataniidae. Based on the published mitogenomes, we constructed a phylogenetic tree for Limnephiloidea and conducted a preliminary analysis of its advanced phylogeny. The ML and BI analyses recover the monophyly of Apataniidae and Limnephilidae. Except for PCG, BI tree based on other matrices consistently showed the topology: (Apataniana + (Moropsyche + (Apatidelia + Apatania))). The taxonomic status of Apatania and Apatidelia were also preliminarily explored. The mitochondrial genome of Apataniidae provides critical genomic resources for understanding the phylogenetic relationships of Apataniidae.

Environmental DNA metabarcoding offers an efficient and non-invasive solution for aquatic biomonitoring surveys, particularly demonstrating remarkable potential in macroinvertebrate research. In this study, we systematically analyzed 322 articles in the Web of Science Core Collection from 2010 to 2024 using bibliometric methods to reveal the research trends and technological advances in the field of macroinvertebrate surveys based on eDNA metabarcoding technology. The results showed that the number of annual publications has increased rapidly since 2012, with the United States (n = 58), France (n = 43), and Canada (n = 39) as the main contributing countries, and the most intensive collaboration network was observed among Europe countries. A keyword analysis shows that, in the past five years, the research direction has shifted to novel methodologies including multi-marker approaches, quantitative PCR, digital PCR, and other molecular detection platforms and high-throughput sequencing technology, with the integration of machine-learning and deep-learning architecture significantly improving the taxonomic resolution of data analysis. Despite the advantages of eDNA metabarcoding technology in terms of sensitivity and efficiency, persistent challenges including false positives/negatives in detection and incomplete reference databases are still the main challenges. This study provides methodological evidence for standardizing eDNA protocols in benthic assessments while identifying critical knowledge gaps.

Lepidostomatidae is a relatively large family of the infraorder Plenitentoria (Integripalpia), comprising four fossil genera and seven extant genera. Lepidostomatid adults exhibit pronounced sexual dimorphism and have thus been referred to as the ‘cabinet of curiosities’ within Trichoptera. However, only five annotated mitogenomes of Lepidostoma have been recorded in the GeneBank database, and some of these mitogenomes are incomplete. To better understand the structure of mitogenome and phylogenetic relationships of Lepidostomatidae, we present mitogenomes of 13 Lepidostoma species and one Paraphlegopteryx species for the first time. We combined these new mitogenomes with previously published data for a comparative analysis. The results showed that the structure of mitogenome was relatively conserved, the nucleotide composition was significantly AT biased, and the control region showed the highest A + T content. Evolutionary rate analysis showed that all protein-coding genes underwent purification selection. The phylogenetic relationships supported the monophyly of Lepidostomatidae and restored the taxonomic positions of the two subfamilies. Meanwhile, two monophyletic branches (Lepidostoma ferox branch and Lepidostoma hirtum branch) within the genus Lepidostoma were also strongly supported. These findings significantly advance our understanding of the mitogenome and phylogeny of Lepidostomatidae.

The genus Phraepsyche Malicky and Chantaramongkol, 2000, is endemic to the Oriental region, currently comprising five species. However, its species diversity remains incompletely explored, and genetic data for this genus are completely lacking. Here, we describe a new species of Phraepsyche from southwestern China, present a distribution map of the species in the genus, and update the key to Phraepsyche. Meanwhile, we obtained the first genetic data (mitochondrial genome) for Phraepsyche and performed assembly, annotation, and structural analysis of the mitogenome. Furthermore, we inferred the phylogenetic position of Phraepsyche using representatives of other genera of Odontoceridae.

Jingpo Lake in Northeast China is a vital aquatic ecosystem, yet it lacks baseline molecular data for its insects. Trichoptera (caddisflies) are excellent ecological bioindicators, but their accurate identification is often hindered by morphological similarities, life-stage limitations, and insufficient DNA barcode records. To address this gap, this study combined morphological identification with DNA barcoding to establish a local reference database. From 285 collected adult caddisflies, 105 representative specimens were selected for genetic analysis. The survey identified 22 species across 9 families, revealing four new records for China and six for Heilongjiang Province. Analyses confirmed the high efficacy of the COI marker, demonstrating low intraspecific genetic divergence (0.78%) and high interspecific divergence (17.80%), with a clear barcode gap separating all examined species. Species accumulation curves indicated robust sampling of the main genera, although expanded collection efforts could still uncover additional species. In conclusion, this study provides a valuable DNA barcode reference library for Trichoptera in the Jingpo Lake region. It establishes foundational data for regional biodiversity inventories and future ecological monitoring based on environmental DNA (eDNA) or metabarcoding approaches.