Multigenerational inheritance of parasitic stress memory in Drosophila melanogaster

Organisms detect harmful environmental conditions and employ strategies to protect themselves. Additionally, they can communicate these experiences to the next generation or beyond through non-DNA sequence-based mechanisms, known as intergenerational or transgenerational epigenetic inheritance, respectively. Using a specialist larval parasitoid, Leptopilina boulardi, and its host, Drosophila melanogaster, we demonstrate that parental experience of parasitic stress leads to increased survivability in the immediate offspring of the host. Furthermore, we observe that this increased survivability in response to parasitic stress is transmitted transgenerationally when the grandparents, but not the parents, have been exposed to the parasitoid. This increased survivability is primarily inherited through male parents, with one form of effect being enhanced immune priming at the larval stage. Our study suggests that stress exposure during the pre-adult stage of the host provides lifetime benefits for its progeny, enabling them to better cope with future parasitic attacks.