Persistent effects of maternal parasitic infection on offspring fitness: implications for adaptive reproductive strategies when parasitized

1. Maternal effects on offspring phenotype may represent adaptive strategies to optimize maternal or offspring fitness given the maternal environment. The effect of maternal parasitic infection on offspring phenotype has been largely ignored, despite the potential for such effects to be components of a maternal reproductive strategy. In addition, the persistence and fitness consequences of maternal effects are understudied, particularly with respect to research on maternal parasitic infection. 2. Deer mice (Peromyscus maniculatus) increase reproductive output by weaning heavier offspring when infected with a schistosome parasite (Schistosomatium douthitti). Here, I examine the persistence of maternal effects on offspring phenotype and evaluate potential consequences of maternal parasitic infection for offspring lifetime fitness. 3. Offspring of parasitized females are born heavier, and this mass advantage persists in sons until adulthood. Because adult body mass is known to influence adult reproductive success in deer mice, parasitized mothers would have produced sons of higher reproductive success. 4. Neither maternal infection nor offspring mass influenced adult son aggression. Survival was enhanced for heavier offspring post-weaning. 5. The production of heavier offspring by parasitized females, therefore, led to increased offspring fitness through enhanced survival and potentially reproductive success. The resultant increase in current maternal reproductive success in response to possible infection-induced decreases in future reproductive opportunities supports the hypothesis that infected females trade-off between current and future reproduction.