【Aim】To clarify the key characteristics and indexes of male external genitalia of grasshoppers for accurately identifying the grasshoppers in grasslands of the Jiuquan Area of Gansu, northwestern China. 【Methods】 We dissected and compared the structure of male external genitalia of adults of 12 species of grasshoppers collected from grasslands of Jiuquan, Gansu, which belong to seven genera of three families (Oxya chinensis and O. adentata of Oxya of Catantopidae; Oedaleus manjius and O. infernalis of Oedaleus, Epacromius coerulipes and E. tergestinus tergestinus of Epacromius, Sphingonotus
ningsianus and S. yenchihensis of Sphingonotus, Compsorhipis davidiana of Compsorhipis of Oedipodidae; Chorthippus brunneus huabeiensis and C. albonemus of Chorthippus, and Euchorthippus unicolor of Euchorthippus of Arcypteridae). And we analyzed eight indexes of male external genitalia by principal component analysis. 【Results】The epiphalli of the genus Oxya in the family Catantopidae are narrow bridge-shaped and have no ancorae, and the zygomata of phallic complex are very wide, while the epiphalli of the other 10 species of grasshoppers were wide bridge-shaped and have ancorae, and the zygomata of phallic complex are narrow. The basal vaves of penis of phallic complex in Oedipodidae are wide and round, but in Arcypteridae, they are hook-shaped. About the shape of lophi, it varies significantly among different genera. In addition, the principal component analysis of eight indexes of male externul genitalia of 12 species of grasshoppers showed that there were two principal components with the eigenvalues greater than 1.00, which were the 1st principal component and the 2nd principal component, respectively, with a total contribution rate up to 78.27%. The main components of the 1st principal component included the outer distance of ancorae, the outer distance of posterior projection, the inner distance of ancorae, the height of ancorae, the distance between the two ancoraes, and the width of bridge, and the main component of the 2nd principal component was the length-to-width ratio of phallic complex. 【Conclusion】 The male external genitalia of grasshoppers possess significant differences among families, genera and species, which can be used to distinguish the 12 species of grasshoppers in Jiuquan Area. The relative position of ancorae, the outer distance posterior projection, the width of bridge and the size of the phallic complex in the male external genitalia are principal indexes when distinguishing these 12 species of grasshoppers.

【Aim】 Identifying butterfly species accurately and monitoring changes in butterfly community diversity dynamically play a significant role in habitat quality assessment and ecological environment restoration. This study aims to develop a Local-Global-VIT fine-grained classification algorithm-based method for butterfly recognition to address the limitation of existing butterfly recognition methods by relying solely on global features but overlooking local features, consequently, leading to inadequate recognition of ecological images. 【Methods】 A dataset of 25 279 butterfly images from 200 species across five families for recognition was used. Various data augmentation techniques were employed to expand the image data. By utilizing the hierarchical structure and self-attention mechanism of vision transformer (VIT), the method selected local tokens layer by layer and retains them until the final layer learned the discriminative local features of butterflies. High-level global tokens were aggregated to mitigate interference from complex backgrounds. Contrastive loss was optimized to widen the inter-class gap and improve differentiation. Additionally, a reasonable learning rate adjustment strategy and transfer learning methods were applied to optimize the model’s convergence process, thereby improving performance without increasing the number of parameters. 【Results】 The recognition accuracy of the Local-Global-VIT algorithm reached 91.20% on the extensive fine-grained Butterfly-200 public dataset, which represented an improvement of 1.15% over previous methods. Therefore, the accuracy of the Local-Global-VIT algorithm exhibited an enhancement by 1.83% and 0.64%, respectively, and its F1-scores increased by 1.89% and 0.88%, respectively, in comparison to the state-of-the-art general pest recognition algorithm EfficientNet_b0 and the fine-grained classification algorithm, TransFG. 【Conclusion】 The Local-Global-VIT algorithm effectively addresses the challenge of distinguishing between significantly different intra-class characteristics and subtle inter-class differences in butterflies through fine-grained recognition, and can accurately identifies various butterfly species, thus contributing to the efficient habitat quality assessment.