The effects of dietary yeast on the cellular immune response of Drosophila melanogaster against the larval parasitoid, Leptopilina boulardi.

The role of dietary yeast in Drosophila melanogaster cellular immunity was investigated. Host larvae deprived of yeast immediately after parasitization by the cynipid wasp Leptopilina boulardi encapsulated a significantly lower percentage of the parasitoid's eggs than hosts transferred to a medium with yeast. When the transfers of hosts were made 24 hr after exposure to the parasite, diet had no effect on the immune response that had commenced prior to the transfers. This study demonstrates for the first time the effect of a specific dietary component on the immune responsiveness of Drosophila against a larval parasitoid.