New Records of Trichogrammatidae (Hymenoptera) Egg Parasitoids of Helicoverpa spp. in Chickpea Agroecosystems

Abstract

Field surveys were conducted in chickpea-growing agroecosystems to document the diversity and distribution of trichogrammatid egg parasitoids associated with Helicoverpa species infesting chickpea crops. Sampling was carried out across multiple production regions during different cropping seasons through collection of host eggs from chickpea foliage and laboratory rearing of emerging parasitoids. Adult parasitoids were identified using morphological and molecular techniques to determine species composition and establish new faunal records. Morphological examination based on antennal structure, wing venation, body coloration, and genital characteristics confirmed the occurrence of several species belonging to the family Trichogrammatidae, including previously unreported records from chickpea ecosystems in the surveyed areas. Molecular characterization using mitochondrial cytochrome oxidase I (COI) gene sequencing further supported species identification and phylogenetic placement within recognized trichogrammatid lineages. Parasitoid activity was closely associated with the seasonal abundance of Helicoverpa eggs and environmental conditions prevailing during the chickpea growing period. Higher parasitism rates were observed during moderate temperature and relative humidity conditions that favored both host oviposition and parasitoid development. Certain parasitoid species exhibited broad host associations with multiple Helicoverpa species, whereas others demonstrated relatively narrow host preferences. Natural parasitism levels indicated the ecological importance of indigenous trichogrammatid parasitoids in suppressing early developmental stages of Helicoverpa populations under field conditions. Chickpea fields managed with reduced insecticide application supported greater parasitoid diversity and higher parasitism activity compared with intensively treated production systems. The discovery of new trichogrammatid records expands current knowledge of parasitoid biodiversity in pulse agroecosystems and highlights the significance of native egg parasitoids in sustainable biological control programs.