Morphological and Molecular Identification of Diaphania Species (Lepidoptera: Crambidae) Damaging Cucurbit Crops

Abstract

Diaphania species (Lepidoptera: Crambidae) are important defoliators of cucurbit crops, causing significant yield losses through larval feeding on leaves, flowers, and developing fruits. Accurate identification of these closely related species is essential for effective pest management and ecological studies. The present study focused on the morphological and molecular identification of Diaphania species damaging cucurbit crops in major cultivation areas. Larvae and adults were collected from infested cucumber, pumpkin, and melon fields showing characteristic feeding damage. Morphological characterization was performed based on adult wing coloration, genitalia structure, larval body markings, and chaetotaxy patterns using standard taxonomic keys. Considerable morphological variation was observed among collected specimens, indicating the presence of multiple Diaphania species within cucurbit agroecosystems. Molecular identification was carried out using DNA barcoding of mitochondrial cytochrome c oxidase subunit I (COI) gene sequences, followed by phylogenetic analysis to resolve species-level relationships. The results confirmed the presence of distinct Diaphania species complexes associated with cucurbit crops, with clear genetic divergence among populations. Molecular data supported morphological findings and improved resolution in distinguishing cryptic or closely related species. Phylogenetic analysis revealed clustering patterns corresponding to species identity and geographical origin, suggesting both regional adaptation and host-associated distribution. The integration of morphological and molecular approaches enhanced the accuracy of species identification and clarified taxonomic relationships within the genus. The findings provide important insights into the diversity and distribution of Diaphania species in cucurbit production systems and support the development of targeted integrated pest management strategies for sustainable cucurbit cultivation.