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.

Background: Chironomidae occupy a pivotal position within global aquatic ecosystems. The unique structural attributes of the mitochondrial genome provide profound insights and compelling evidence, underpinning the morphological classification of organisms and substantially advancing our understanding of the phylogenetic relationships within Chironomidae. Results: We have meticulously sequenced, assembled, and annotated the mitogenomes of Tanypus chinensis (Wang, 1994) and Tanypus kraatzi (Kieffer, 1912), incorporating an additional 25 previously published mitogenomes into our comprehensive analysis. This extensive dataset enables us to delve deeper into the intricate characteristics and nuances of these mitogenomes, facilitating a more nuanced understanding of their genetic makeup. Conclusions: The genomic nucleotide composition of T. kraatzi was 39.10% A, 36.51% T, 14.33% C, and 10.06% G, with a total length of 1508 bp. The genomic nucleotide composition of T. chinensis was 39.61% A, 36.27% T, 14.55% C, and 9.57% G, with a total length of 1503 bp. This significant enrichment of the chironomid mitogenome library establishes a novel foundation for further exploration in the realm of phylogenetics.

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.

As the largest tributary of the Yangtze River and a core area of the Middle Route of the South-to-North Water Diversion Project, the Han River Basin holds significant ecological importance regarding the impacts of land use and water environment changes on aquatic ecosystems. Existing studies have mostly focused on local reaches of the upper or middle–lower Han River, and systematic investigations into the associations between macroinvertebrate communities and environmental factors at the entire basin scale remain scarce. The niche characteristics and environmental drivers of macroinvertebrate community structure in the Han River Basin, China, were evaluated using a variety of diversity metrics and statistical methods. The results showed that: (1) A total of 91 macroinvertebrate taxa were identified during 2022–2023, with Insecta as the dominant group. Species richness in the upstream reaches increased in 2023, and the degree of differentiation between the upstream and the middle–lower reaches was markedly weaker than that in 2022. (2) Significant interannual differences in macroinvertebrate community structure were detected (PERMANOVA, p < 0.05), and taxa such as Polypedilum sp., Orthocladius sp., and Gammaridae collectively accounted for 35.6% of the dissimilarity among communities. (3) The overall niche breadth of dominant taxa was relatively low, whereas niche overlap decreased significantly in 2023, indicating a community niche pattern characterized by “low competition–high differentiation”. (4) Total phosphorus (TP) and total nitrogen (TN) were the core water environmental factors driving changes in community structure, while forested land was the key land use factor, and their synergistic effects jointly regulated the composition and diversity of macroinvertebrate communities.