The scarab beetle is an herbivorous pest that causes considerable damage to various agricultural crops. The characteristics of the hind wings have rarely been utilized as indicators for species identification, particularly within the genus Holotrichia. To evaluate the potential of hind wing traits in species identification and gender differentiation, we extracted 25 landmarks from 125 samples of three beetle species (Holotrichia diomphalia, H. titanis, and H. oblita) using TPSDig2 v2.31, with each hind wing image analyzed three times. These landmarks were employed to analyze variations in wing size and shape among species and sexes, and a cross-validation test was conducted in MorphoJ v1.06 to assess classification accuracy. The results demonstrate that both female and male samples exhibit significant differences in wing size and shape variations across species, but not between sexes. Allometry accounts for 16.92% and 25.35% of total shape variation in females and males, separately. After correcting for allometric effects, classification accuracy improves for these beetles. From further analysis, it can be observed that female wings exhibit a wider and shorter morphology in comparison to the more slender and elongated wings of males. In terms of interspecific differences, H. oblita females displayed narrow and elongated wings, whereas H. diomphalia females had a more rectangular wing shape. Among males, the degree of wing narrowness decreased in the order of H. oblita, H. titanis, and H. diomphalia.

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 Asiatic apple leafminer, Phyllonorycter ringoniella (Matsumura), is a significant secondary pest of apple trees in Northeast Asia. To better understand its population dynamics, a population model based on temperature-developmental relationships was constructed. This model includes three sub-models: spring emergence, immature stage transition, and adult oviposition. Field data were collected from sex-pheromone baited traps in apple orchards in Andong, Korea, dur-ing 2015 and 2016 to validate the model. Simulations under six pesticide-natural enemy scenari-os showed that the population size of each generation was best simulated when weighted mor-tality factors for pesticides and natural enemies were applied. Using daily temperature inputs, the model demonstrated that P. ringoniella typically undergoes five generations per year, with peak times predicted within a seven-day margin of field data. Sensitivity analyses revealed that population size was influenced by total fecundity and the larval stage model, but peak times remained consistent despite parameter changes. Higher temperatures led to earlier adult peak dates, especially in summer generations. This model serves as a fundamental tool for estimating population dynamics and abundance changes of P. ringoniella and can guide the timings of pesti-cide application. Further validation is necessary to test the model's efficacy in controlling pests in apple orchards.

Reliable traits are needed for identification of tea (Camellia sinensis) cultivars, yet the stability of leaf morphology and color across leaf positions remains unclear. This study evaluated inter-cultivar variation and positional stability in leaf morphological, RGB color, and SPAD traits in six predominant cultivars. One-year-old shoots were sampled in a completely randomized design, and five fully expanded leaves below the apical bud were analyzed. SPAD values were measured with a chlorophyll meter, and scanned images were used to extract contour and RGB traits. Data were analyzed using ANOVA, correlation analysis, PCA, and discriminant analysis. Leaf morphology differed among cultivars and leaf positions, with significant cultivar-by-position interactions; however, the width-to-length ratio differed among cultivars but remained stable across positions in these cultivars. SPAD values increased with leaf position and were strongly associated with RGB components, being negatively correlated with R and G and positively correlated with B. Morphological traits explained 52.988% of total variance in PCA and yielded 64.6% overall classification accuracy, with LaoHan showing the highest accuracy (83.3%). Misclassification was concentrated among genetically similar cultivars. These findings suggest that stable leaf shape proportions and SPAD–RGB relationships provide useful descriptors, whereas genetic relatedness limits morphology-based cultivar identification under the present conditions.