The Colorado potato beetle is a notorious agricultural pest with remarkable adaptability and insecticide resistance. This study conducted comprehensive transcriptome analysis across multiple developmental stages and tissues, focusing on the cytochrome P450 monooxygenase gene family. Using RNA-seq data from 65 datasets, we identified significant transcriptional reprogramming during key developmental transitions, particularly from egg to first instar larva and from third instar larva to adult, reflecting critical biological processes, including feeding initiation and metamorphosis. We identified 3616 tissue-specific genes, with the testis exhibiting the highest transcriptional specialization (1182 genes). Genome-wide screening revealed 78 P450 genes distributed across four major clans with an uneven chromosomal distribution. Expression analysis demonstrated six distinct clusters with tissue and developmental stage-specific patterns. Evolutionary analysis identified five P450 genes under strong positive selection. Analysis of mRNA sequence polymorphisms revealed developmental stage and tissue-dependent patterns, with elevated mutation frequencies in early developmental stages and specific tissues. These distinct tissue and developmental stage-specific mutation patterns in P450 transcripts highlight the dynamic regulation of detoxification genes. Our findings advance the understanding of the molecular mechanisms underlying the beetle’s ecological success and provide valuable targets for developing novel pest management strategies.

The study of plant genomics has significantly deepened our understanding of plant evolution and adaptation from a microscopic perspective

Insect metamorphosis is a complex developmental process regulated by hormonal signaling and gene transcription. To elucidate its transcriptional regulatory mechanisms, we examined chromatin accessibility dynamics during metamorphosis in two holometabolous insects, Harmonia axyridis and Drosophila melanogaster, using ATAC-seq. Our analysis revealed distinct stage-specific chromatin accessibility patterns, with peak accessibility during the prepupal stage in H. axyridis and the wandering larval to prepupal transition in D. melanogaster. Through analysis of differential accessibility regions (DARs), we identified enrichment of metamorphosis-related processes including cell morphogenesis, tissue remodeling, and hormone signaling pathways via Gene Ontology and KEGG pathway analyses. Integration of chromatin accessibility with gene expression data revealed 608 conserved genes exhibiting coordinated accessibility and expression changes across both species. Additionally, we constructed a regulatory network centered around four key transcription factors (dsx, E93, REPTOR, and Sox14) that form core regulatory modules controlling metamorphosis. This study provides novel insights into the epigenetic landscape of insect metamorphosis and establishes a foundation for understanding the transcriptional regulatory mechanisms governing this critical developmental process.

Sex-biased gene expression is a fundamental driver of sexual dimorphism and plays an important role in evolutionary divergence across species. Here, we conducted a comparative evolutionary analysis of sex-biased genes (SBGs) in 13 insect species spanning four major orders: Hemiptera, Diptera, Lepidoptera, and Coleoptera. In total, 42,488 SBGs were identified, with low interspecific conservation—86.5% of orthogroups were shared by six or fewer species. Phylogenetic analyses showed that SBGs generally follow evolutionary trajectories similar to other protein-coding genes but show branch length differences suggestive of accelerated evolution in Drosophila virilis and Tribolium castaneum. Male-biased genes were more conserved than female-biased genes, which often showed reversed expression patterns, particularly in T. castaneum. Functional annotation of three rapidly evolving orthogroups in T. castaneum indicates possible associations with sex-specific traits such as lifespan, muscle development, and immunity, which should be considered hypotheses for future functional validation. These findings highlight the complex evolutionary dynamics of sex-biased genes and their contributions to phenotypic diversity and adaptive evolution in insects, providing a basis for future studies on the molecular mechanisms of sexual dimorphism and lineage-specific adaptations.