Influence of handling and conditioning protocol on learning and memory of Microplitis croceipes

Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) learns odors in association with both hosts and food. The food‐associated ‘seeking’ behavior of M. croceipes was investigated under various training protocols utilizing the conditioning odor, 3‐octanone. We investigated the effects of odor training, or its lack, training duration, training frequency, time elapsed after training, wasp hunger state, and training reinforcement, on the food‐seeking responses of M. croceipes females. We found that odor‐trained females show strong food seeking responses, whereas non‐odor‐trained females do not respond to the odor, and that a single 10 s association with the odor whilst feeding on sugar water subsequently conditioned the wasps to exhibiting significant responses to it. Increases in training time to more than 10 s did not improve their responses. Repetition of the food–odor associations increased a wasp's recall, as well as its response over time, compared to a single exposure. Repeated exposure to the learned odor in the absence of a food reward decreased the responses of less hungry individuals. However, the level of response increased significantly following a single reinforcement with the food–odor association. Understanding the factors that influence learning in parasitoids can enhance our ability to predict their foraging behavior, and opens up avenues for the development of effective biological detectors.