Parasitism Efficiency of Bracon hebetor (Hymenoptera: Braconidae) on Ephestia kuehniella Larvae Under Different Temperature and Humidity Levels

Abstract

Parasitism efficiency of Bracon hebetor (Hymenoptera: Braconidae) on larvae of Ephestia kuehniella was evaluated under different temperature and humidity regimes to determine the influence of environmental conditions on parasitoid performance. Laboratory experiments were conducted using controlled climate chambers, where larval exposure to parasitoids was assessed across a range of temperature and relative humidity combinations. Key biological parameters including parasitism rate, larval mortality, parasitoid emergence, and progeny production were recorded. Results demonstrated that parasitism efficiency varied significantly with environmental conditions, with optimal performance observed at moderate temperature and relative humidity levels that supported both host activity and parasitoid development. Elevated temperatures accelerated parasitoid activity but reduced survival and emergence at extreme levels, while low temperatures delayed parasitism and prolonged developmental duration. Relative humidity also influenced host–parasitoid interaction, with moderate humidity favoring higher parasitism success and adult emergence, whereas very low or excessively high humidity negatively affected parasitoid efficiency. The study highlights the sensitivity of B. hebetor performance to abiotic factors and underscores the importance of environmental regulation in biological control programs. Findings suggest that successful application of B. hebetor in stored-product pest management requires consideration of microclimatic conditions to maximize parasitism efficiency against E. kuehniella populations. These results contribute to optimizing augmentative biological control strategies in storage and post-harvest environments.