Exit Holes as Ecological Clues: Understanding the Guild Structure of Heteropteran Egg Parasitoids in India

Heteroptera, a suborder under Hemiptera, includes many phytophagous and predatory species of true bugs of economic importance. Their populations are often regulated by hymenopteran egg parasitoids. The present study explored the egg parasitoid associations of four heteropteran families namely, Alydidae, Coreidae, Pentatomidae, and Plataspidae across selected agroecosystems in Kerala and West Bengal. Focusing on an alternative, non-invasive approach, we analysed the morphology and position of parasitoid emergence holes on heteropteran egg masses, resulting from the activity of ten major hymenopteran parasitoid genera. The distinct and diagnostic exit hole features could reliably infer parasitoid guild structure even in the absence of emerged adults. This field-based rapid assessment technique provides valuable ecological insights, allowing the evaluation of parasitoid diversity, host use strategies, and temporal trends from empty egg clutches. The results hold promise for a rapid biodiversity monitoring in species-rich and hyper diverse landscapes, offering a simpler and cost-effective tool. This study represents the first attempt in India to systematically characterize parasitoid exit hole morphology in heteropteran hosts and demonstrates its potential application in ecological research and biological control programs.