Lignocellulose, as the key structural component of plant biomass, is a recalcitrant structure, difficult to degrade. The traditional management of plant waste, including landfill and incineration, usually causes serious environmental pollution and health problems. Interestingly, the xylophagous beetle, Trypoxylus dichotomus, can decompose lignocellulosic biomass. However, the genomics around the digestion mechanism of this beetle remain to be elucidated. Here, we assembled the genome of T. dichotomus, showing that the draft genome size of T. dichotomus is 636.27 Mb, with 95.37% scaffolds anchored onto 10 chromosomes. Phylogenetic results indicated that a divergent evolution between the ancestors of T. dichotomus and the closely related scarabaeid species Onthophagus taurus occurred in the early Cretaceous (120 million years ago). Through gene family evolution analysis, we found 67 rapidly evolving gene families, within which there were 2 digestive gene families (encoding Trypsin and Enoyl-(Acyl carrier protein) reductase) that have experienced significant expansion, indicating that they may contribute to the high degradation efficiency of lignocellulose in T. dichotomus. Additionally, events of chromosome breakage and rearrangement were observed by synteny analysis during the evolution of T. dichotomus due to chromosomes 6 and 8 of T. dichotomus being intersected with chromosomes 2 and 10 of Tribolium castaneum, respectively. Furthermore, the comparative transcriptome analyses of larval guts showed that the digestion-related genes were more commonly expressed in the midgut or mushroom residue group than the hindgut or sawdust group. This study reports the well-assembled and annotated genome of T. dichotomus, providing genomic and transcriptomic bases for further understanding the functional and evolutionary mechanisms of lignocellulose digestion in T. dichotomus.

Cheirotonus jansoni is a nationally protected and ornamental beetle species endemic to southern China, northern Burma, and Vietnam. Due to habitat degradation and illegal collection, its populations have declined significantly, prompting urgent conservation efforts. Here, we present a high-quality, chromosome-level genome assembly for C. jansoni to support future ecological and evolutionary studies. Male adults were collected from Qingliangfeng national nature reserve, and high molecular weight DNA was extracted for sequencing. The genome was assembled using PacBio long reads and scaffolded with Hi-C chromatin conformation data. The final assembly spans approximately 620.03 Mb, with a scaffold N50 of 101.60 Mb and 98.9% of sequences anchored to 10 chromosomes. Benchmarking with BUSCO revealed a 93.6% completeness rate, indicating high assembly quality. This genomic resource provides a valuable foundation for studying the genetic basis of adaptation, population decline, and conservation planning in C. jansoni and related species.

The potato scab-gnat, Pnyxia scabiei, was recorded as a pest attacking potato tubers and greenhouse cucumber plants. The mitochondrial genome of a total length of 15,437 bp was sequenced, including 13 protein-coding genes, 22 tRNA genes, and two rRNA genes with A + T content of 77.2%. Six gene overlaps were found from 1 to 34 bp. Phylogenetic analysis showed that P. scabiei was closely related to Trichosia lengersdorfi + Sciara ruficauda. The study provided further data for species diversification in Sciaridae.

Four morphologically allied species of the Bradysia hilaris group were studied from China. In a DNA metabarcoding based dipteran diversity study in Zhejiang, eastern China, a hyper-abundant sciarid species was discovered. It was further recognized in this study to be new to science, Bradysia tianmuensis Du & Huang sp. nov., as well as a morphologically similar species, Bradysia curvula Du & Huang sp. nov. Both new species were found to be fairly similar morphologically to the holotype of Bradysia noduspina Yang, Zhang & Yang, 1993 from Guizhou in western China. However, the paratype of B. noduspina appeared to be different from the holotype and determined to be new to science, Bradysia chikunae Du & Huang sp. nov. A phylogenetic tree of all the available 31 COI sequences of the Bradysia hilaris group was provided. Molecular work conducted in the current study also supports Bradysia tianmuensis Du & Huang sp. nov. and Bradysia curvula Du & Huang sp. nov. as new to science thus the four species were described or redescribed accompanied by detailed imagery of habitus and other characters useful for determination.

In this study, two new species of Setostylus (Diptera: Keroplatidae: Keroplatinae), S. tridigitus sp. n. and S. triumphus sp. n. are described, with a key to all the species of the genus. Male habitus and images of diagnostic morphological characteristics are provided. Status of these two new species is also supported by the genetic distances and neighbor-joining (NJ) tree in the DNA barcode analysis.