Microbiome mediates oxidative costs of reproduction

Author(s): Jacob S, Parthuisot N, Callat-Michel A, Helfenstein F, Heeb P

Summary:

Parasites exert important selective pressures on host life-history traits. By affecting allocation trade-offs between reproduction and self-maintenance, they have major consequences for host reproductive success and survival. Microbiome is a major part of earth biomass, including pathogenic and commensal microorganisms. To date experimental studies that examine how the microbiome shapes host life-history traits are still lacking. Here we modified nest microbial communities of wild breeding great tits (Parus major) to test whether the microbiome mediates the oxidative cost of reproduction. We found that microbiome affected the relationship between fledgling number and adult oxidative damage. Adults raising a large number of nestlings show higher oxidative damage in control and high bacterial density treatments, whereas this trade-off was absent when decreasing bacterial densities. This study provides the first experimental evidence for a role of environmental microbiome in mediating the oxidative costs of reproduction. Our results show that the microbiome may constitutes a fundamental factor shaping animal life-history traits that need to be considered in future studies.