Search Results (4)

The family Limoniidae is the most species-rich within the order Diptera. The classification of this family is still unresolved and is based largely on morphological studies and the opinions of a few specialists. The rapid advancement of molecular techniques has created new opportunities to address long-standing systematic challenges. Nevertheless, relatively few studies have used molecular data to refine our understanding of Limoniidae and its relationships with allied lineages. In the present study, we reviewed publications that applied molecular approaches to improve the classification of Limoniidae and clarify its relationships with related groups. Relevant studies were identified through the literature section of the Catalogue of the Craneflies of the World using the keywords “classification”, “systematics”, and “molecular”. We retained only studies that employed molecular data to investigate the classification of Limoniidae, the phylogenetic position of the family within Tipuloidea, and the placement of Tipulomorpha within the dipteran tree. The studies reviewed consistently support the conclusion that Limoniidae is not monophyletic. In contrast, Tipulomorpha is consistently recovered as a monophyletic lineage, although its position within the dipteran tree remains controversial. Consequently, a satisfactory taxonomic framework has yet to be achieved. Recent advances in high-throughput sequencing and the generation of large-scale molecular datasets provide unprecedented opportunities to resolve these systematic uncertainties. We therefore advocate expanding both taxon sampling and the number of genetic markers included in phylogenetic analyses. Ultimately, a coordinated effort among research groups and institutions is likely to represent the most effective strategy for resolving the taxonomy and evolutionary relationships of Limoniidae. Full article

Saproxylic insects of the infraorders Bibionomorpha and Tipulomorpha (Diptera) are ecologically important components of forest ecosystems, associated with dead wood and contributing to nutrient cycling and food webs. Despite their diversity, the influence of climatic variables on saproxylic nematoceran communities remains poorly understood. This study examined the effects of precipitation, air temperature, and relative humidity on the abundance, species richness, and diversity of saproxylic nematoceran flies in three Lithuanian nature reserves from 2016 to 2020. In total, 793 specimens representing 10 families were collected using trunk-emergence traps. Statistical models showed that precipitation was significantly positively associated with species richness, total abundance, and Shannon’s diversity, whereas temperature and humidity were excluded as non-significant predictors. These results highlight precipitation as a key environmental driver shaping saproxylic fly assemblages and suggest potential sensitivity of these communities to reduced moisture availability under future climate change scenarios. Full article

Diptera comprises more than 154,000 described species, representing approximately 10–12% of insects. Members have successfully colonized all continents and a wide range of habitats. However, higher-level phylogenetic relationships within Diptera have remained ambiguous. Mitochondrial genomes (mitogenomes) have been used as valuable molecular markers for resolving phylogenetic issues. To explore the effect of such markers in solving the higher-level phylogenetic relationship of Diptera, we sequenced and annotated the mitogenomes of 25 species, combined with 180 mitogenomes from 33 superfamilies of dipteran insects to conduct a phylogenetic analysis based on the PCGsrRNA and PCGs12rRNA datasets using IQ-TREE under the partition model. The phylogenetic analysis failed to recover the monophyly of the two suborders Nematocera and Brachycera. Two of six infraorders within the Nematocera—Tipulomorpha and Ptychopteromorpha—were monophyletic. The ancestral Deuterophlebiidae were a strongly supported sister group of all remaining Diptera, but Anisopodidae, as the closest relative of Brachycera, received only weak support. Three of four infraorders within Branchycera—Tabanomorpha, Xylophagomorpha, and Stratiomyomorpha—were, respectively, supported as a monophyletic clade, except Muscomorpha due to the strong long-branch attraction between Cecidomyiidae and Nycteribiidae. The inferred infraordinal relationships followed the topology Tabanomorpha + (Xylophagomorpha + (Stratiomyomorpha + Muscomorpha)). However, the proposed topology lacks strong statistical support, suggesting alternative relationships remain plausible. Based on mitogenome data alone, we infer that Diptera originated earlier than the Late Triassic at 223.43 Mya (95% highest posterior density [HPD] 166.60–272.02 Mya) and the earliest brachyeran Diptera originated in the mid-Jurassic (171.61 Mya). Full article

Chionea is classified within the Tipuloidea superfamily and predominantly inhabits cold regions. However, its phylogenetic relationships remain contentious. In this study, the first three mitogenomes of Chionea (Diptera: Limoniidae) sampled in northeastern China (Jilin region) were sequenced, and their phylogenetic relationships were reconstructed by integrating these sequences with 30 additional Tipuloidea mitogenomes retrieved from NCBI. Unlike other Tipuloidea species, which are predominantly distributed in relatively warmer regions, this research investigates whether positive selection has acted on the mitogenomes of these three Chionea species due to environmental pressures, thereby elucidating key evolutionary drivers for Chionea. The three mitogenomes of Chionea exhibit characteristic features typical of insect mitogenomes, comprising 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (16S rRNA and 12S rRNA), 22 transfer RNA genes (tRNA), and a single non-coding control region (D-loop). Notably, the secondary structure of trnS1 lacks the DHU arm in all three samples, and UUA (Leu) emerges as the most frequently utilized codon. Furthermore, the COX2 and ND5 genes utilize incomplete stop codons “T”. Utilizing these 13 PCGs, we reconstructed the internal phylogenetic relationships within Tipuloidea, revealing that Chionea tianhuashana and C. sphaerae form sister branches, while (C. tianhuashana + C. sphaerae) constitutes a sister branch to C. crassipes. Moreover, our analysis confirms the monophyly of Tipulidae, Tipula, and Nephrotoma as well as the polyphyly of Tipulinae, Chioneinae, and Limoniidae. In the branch site model analysis, three positively selected sites were detected when Chionea was designated as the foreground branches: COX3 (at position 242), ND5 (at position 535), and ND6 (at position 138). Full article