Trade-offs between reproduction and health in free-ranging African striped mice

International audienceEnergy is limited and must be allocated amongcompeting life-history traits. Reproduction is consideredone of the most energetically demanding life-history stages.Therefore, the amount of energy an individual invests inreproduction might carry fitness costs through reducedenergy allocation to other activities such as health maintenance.We investigated whether reproduction impactshealth in the seasonally breeding African striped mouse(Rhabdomys pumilio). We measured health in individualsthat reproduced (breeders) and individuals that didnot reproduce (their adult offspring) and tested whether:(1) breeders’ health before reproduction was similar tothat of their offspring (representing a baseline); (2) breeders’health deteriorated after reproduction; (3) breeders’health after reproduction was worse than that of their offspring.We collected blood samples from 12 breedingfemales and 11 breeding males both at the onset and atthe end of the breeding season and from 12 adult daughtersand 11 adult sons that did not reproduce at the end of the breeding season. Health was assessed using serumbiochemistry analysis with VetScan Abaxis. Breeders differedconsiderably in their health before and after reproduction,particularly in parameters associated with digestion(lower amylase in males), metabolism (lower albumin,alkaline phosphatase, creatinine and glucose), osmoregulation(lower potassium and phosphorous in females) andimmunity (higher globulin and altered alanine aminotransferase).Our results suggest that with the onset of breedingstriped mice shifted their energy allocation from maintaininghealth to reproduction, indicating that investment intoreproduction carries significant health costs