Timing of breeding and reproductive performance of female European rabbits in response to winter temperature and body mass

Abstract

Environmental conditions frequently affect the reproduction of many mammal and bird species by modulating maternal body condition. In our long-term study of European rabbits, Oryctolagus cuniculus (L., 1758), we investigated the effects of winter weather conditions and body mass on reproductive performance and reproductive timing. Specifically, we tested whether winter temperature affects both reproductive timing and reproductive performance of female rabbits or whether females compensate for low body mass after winter by a shift in the timing of the onset of breeding. Winter body mass loss was higher in years with lower winter temperatures, and the onset of breeding was delayed after these conditions. However, mean size and mass of the first litter of each season and seasonal fecundity were not reduced after harsh winters. At the individual level, females with lower winter body mass started to reproduce later, but we did not find any effects on litter size and mass. In contrast, breeding body mass was a strong predictor of the females' reproductive performance. We also found high between-year variation in mean body mass in late winter but not in mean breeding body mass. In conclusion, our results suggest that the negative effects of winter weather on the body mass of females, which should potentially affect their reproductive performance, were compensated for by delaying the onset of breeding.