Factors affecting maternal care in an income breeder, the European roe deer

International audience1. Maternal care is a major component of demographic tactics in mammals. In ungulates most work has been done on capital breeders (e.g. bighorn sheep), which rely heavily on body reserves to raise their young. Roe deer, in contrast, are close to the income breeder end of the capital±income breeder continuum, and show high levels of maternal care. 2. The aim of this study was to explore the factors determining the level of mater- nal care in roe deer, in particular the e€ects of maternal body weight, mother's par- ity, litter size and year of birth on the amount of prenatal care (i.e. the average mass of an o€spring multiplied by the number of o€spring) and postnatal care (i.e. the average growth rate of the o€spring multiplied by their number). The study was carried out on a captive population of roe deer fed ad libitum, and in a wild population. 3. In both populations prenatal care increased with increasing maternal body weight. In the population fed ad libitum this e€ect was found in light females only (< 22 kg); in the wild population the positive relationship between maternal body weight and prenatal care was entirely accounted for by variation in litter size (i.e. heaviest females produced larger litters) and density (i.e. females were lightest in years with high population density). Parity did not a€ect prenatal care. 4. In 14 females fed ad libitum there was no relationship between postnatal care and maternal body weight. Multiparous females had higher levels of postnatal care. In contrast, 20 wild females showed a positive relationship between postnatal care and maternal body weight, and only litter size a€ected the level of postnatal care. 5. Even after accounting for the confounding e€ects of maternal body weight, par- ity, litter size and population density, we found no trade-o€ between pre- and post- natal care in any of the two populations. The conditions under which the pattern of maternal care could impose trade-o€s that a€ect the individual o€spring are dis- cussed