Insect odorant-binding proteins (OBPs) are promising molecular targets for developing novel pest management strategies by modulating chemoreception-driven behaviors. The tea gray geometrid Ectropis grisescens (Lepidoptera, Geometridae) is a major pest in tea plantations, causing substantial economic losses in China. In this study, we identified 18 OBPs from E. grisescens antennal transcriptome. All of the encoded proteins possessed N-terminal signal peptides and conserved cysteine residues, behaviors which are characteristic of insect OBPs. Phylogenetic analysis categorized these proteins into plus-C, minus-C, and classic OBP subfamilies. MEME motif analysis identified conserved sequence features potentially involved in odor detection. Tissue- and sex-specific expression profiling showed that EgriGOBP1-2, OBP3, OBP8, and OBP13 were highly expressed in the antennae of both sexes, suggesting roles in olfactory communication. Among them, EgriGOBP1-2, OBP3, and OBP13 exhibited similar expression levels between males and females, while other EgriOBPs were predominantly expressed in the legs, wings, or other tissues, indicating additional physiological functions beyond chemoreception. To investigate functional specificity, we selected antenna-enriched EgriGOBP2 for ligand-binding analysis. Fluorescence binding assays demonstrated that EgriGOBP2 exhibited broad binding affinity toward 8 of 12 host volatiles and 11 of 12 plant essential oil-derived volatiles. These combined findings lay the foundation for mechanistic studies of chemical recognition in E. grisescens and provide insights into the development of ecologically friendly pest control alternatives.

The nearly complete mitochondrial genome of Sphaeniscus atilius was characterized and annotated in this study. The mitogenome was 16,854 bp in length and encoded 37 typical mitochondrial genes, including 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes, and a control region. The total length of the 13 PCGs was 11,140 bp, and the AT content was 79.8%. There were five types of start codons, ATT ( nad2 , nad3 , nad5 , and nad6 ), ATG ( cox2 , cox3 , atp6, nad4 , nad4l , and cob ), CGA ( cox1 ), as well as ATC ( atp8 ) and ATA ( nad1 ). Most of the PCGs had typical TAA stop codons, except nad5 which terminated with incomplete forms T-. Ile, Phe, Leu and Asn were the most frequently used amino acids in mitochondrial PCGs. Most tRNA genes could be folded into the typical cloverleaf structure, except trnS1 and trnT which lacked the dihydrouridine (DHU) and TΨC arms, respectively. Phylogenetic analyses based on 13 protein-coding genes among the available sequenced species of family Tephritidae by maximum likelihood methods suggested the genus relationship of Tephritidae: (( Bactrocera , Dacus , Zeugodacus ), Felderimyia , Anastrepha ), ( Acrotaeniostola , ( Neoceratitis , Ceratitis ), Euleia , Rivellia ), ( Procecidochares , ( Tephritis , Sphaenisscus ))))). Our results presented the first mitogenome from Sphaeniscus and offer insights into the identification, taxonomy, and phylogeny of Sphaeniscus atilius .

This study aimed to explore the effects of different host tea cultivars on population fitness, as well as the abundance and diversity of gut bacteria of Ectropis grisescens Warren. The feeding preference, survival rate, body length and body weight of E. grisescens larvae were determined on six tea cultivars. Furthermore, 16S rRNA high-throughput sequencing technology was adopted to analyze the community structure and diversity of gut bacteria in larvae fed on Camellia sinensis cv. ‘Xinyang 10’, Camellia sinensis cv. ‘Fudingdabaicha’ and Camellia sinensis cv. ‘Wuniuzao’, and correlation analysis was performed between gut bacterial data and larval growth-development indices. The results revealed significant differences in feeding preference and adaptability of E. grisescens larvae across different tea cultivars. Larvae feeding on C. sinensis cv. ‘Xinyang 10’ achieved the highest survival rate, body length and body weight, showing the optimal fitness; larvae fed on C. sinensis cv. ‘Wuniuzao’ exhibited the lowest values for all measured indices and the poorest fitness. Gut microbiota analysis indicated that Proteobacteria and Firmicutes constituted the core bacterial taxa, yet their relative abundances differed significantly among host treatments. Serratia marcescens was the core gut bacterium in larvae feeding on C. sinensis cv. ‘Xinyang 10’ and C. sinensis cv. ‘Wuniuzao’, whereas Enterococcus flavescens ATCC 49996 dominated the gut of larvae reared on C. sinensis cv. ‘Fudingdabaicha’. Functional profiles demonstrated that gut bacteria of larvae were mainly involved in carbon metabolism, amino acid metabolism, membrane transport, energy metabolism and other pathways. Correlation analysis showed that larval growth-development indices were positively correlated with Serratia marcescens. Collectively, host tea cultivars shape the adaptability of E. grisescens, and the underlying mechanism is potentially associated with the composition, abundance and function of gut bacteria. This research provides a theoretical foundation for deciphering the interaction mechanism between tea pests and their hosts from the perspective of gut bacteria and developing novel pest-management strategies.