Parental age at conception on mouse lemurs offspring longevity:sex-specific maternal effects

Parental age at conception often influences offsprings longevity, a phenomenon referred as the "Lansing effect" described in large variety of organisms. But, the majority of the results refer to the survival of juveniles, mainly explained by an inadequate parental care by the elderly parents, mostly the mothers. Studies on the effect of parental age on offsprings longevity in adulthood remain few, excepted in humans for whom effects of parental age are variable according to statistical models or socioeconomic environments. In a small primate which the longevity reaches up to 12 years, we investigated the effects of parental age at conception on the longevity of offspring (N = 278) issued from parents with known longevity. None of the postnatal parameters, including body mass, influenced offsprings longevity. Mothers age at conception significantly affected offsprings longevity in males but not females. By contrast, fathers age at conception did not influence offsprings longevity. When considering the age of the breeding pairs at conception, the older the mother, the lower the longevity of male offspring with a minimum when the father was aged. No such correlation was observed for female offspring. Lastly, the longevity of female offspring was significantly positively related to the longevity of both parents. Compared with current studies, the surprisingly minor effect of fathers age and the major impact of mothers age on male offspring survival, despite favourable conditions, were discussed in relation with the highly seasonal reproduction in mouse lemurs.