Faunistic Survey and Checklist of Ichneumonid Wasps (Hymenoptera: Ichneumonidae) Parasitizing Lepidopteran Larvae in Rice Fields

Abstract

Ichneumonid wasps (Hymenoptera: Ichneumonidae) are among the most important parasitoids in agricultural ecosystems, playing a significant role in the natural suppression of lepidopteran insect pests. In rice production systems, these parasitoids contribute to the biological control of stem borers, leaf folders, and other economically important caterpillar pests that reduce crop productivity. Despite their ecological importance, information on the diversity and distribution of ichneumonid parasitoids in rice agroecosystems remains limited in many regions. The present study was conducted to investigate the faunistic diversity and develop a comprehensive checklist of ichneumonid wasps parasitizing lepidopteran larvae in rice fields. Extensive field surveys were carried out across major rice-growing regions during different crop growth stages. Parasitized lepidopteran larvae were collected from rice plants and reared under laboratory conditions until parasitoid emergence. Adult parasitoids were identified based on morphological and taxonomic characteristics using standard identification keys and comparative descriptions. Observations on host associations, abundance, and seasonal occurrence were also recorded to evaluate parasitoid diversity and ecological relationships. The results revealed a diverse assemblage of ichneumonid wasp species associated with major lepidopteran pests of rice. Several parasitoid species demonstrated strong host associations with stem borers and leaf-feeding caterpillars, indicating their important role in natural pest regulation. Variations in parasitoid abundance and species composition were observed across different rice-growing regions and cropping stages, influenced by environmental conditions and host availability. The study generated a detailed faunistic checklist of ichneumonid parasitoids occurring in rice agroecosystems, including several species of ecological and biological control significance. The findings provide valuable baseline information on parasitoid biodiversity and host associations in rice fields. Understanding the diversity and ecological role of ichneumonid wasps can support conservation biological control programs and contribute to the development of sustainable integrated pest management strategies for rice production systems.