George Washington University Washington, District of Columbia
Parasitoids typically kill their caterpillar hosts upon oviposition or laval emergence from the host. However, some parasitoids are known to manipulate host behavior, enabling them to survive for a short period following larval parasitoid emergence; these caterpillars are termed bodyguards. Bodyguard caterpillars typically remain on or near the vulnerable parasitoid pupae and exhibit defensive behaviors such as thrashing or regurgitating, presumably to protect the pupae from predators and hyperparasitoids. Studies on the effectiveness of bodyguard caterpillars thus far have yielded mixed results. Pieris rapae caterpillars are known to exhibit guarding behavior when they are parasitized by Cotesia glomerata. We sought to determine whether P. rapae bodyguards are effective at protecting C. glomerata cocoons from hyperparasitism in the field. We deployed C. glomerata pupal masses in the field with and without P. rapae bodyguards for two days. We collected the pupal masses from the field and brought them back to the lab until adult parasitoid emergence. We found that C. glomerata pupal masses with their caterpillar bodyguards experienced lower rates of hyperparasitism than those without bodyguards, suggesting that P. rapae can serve as effective deterrents of hyperparasitoids.
