Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, 55108, USA.
Biology, Phillips Academy, Andover, MA, 01810, USA.
Sci Rep. 2021 Feb 17;11(1):4042. doi: 10.1038/s41598-021-83175-3.
In mammalian species with prolonged maternal investment in which high-ranking males gain disproportionate numbers of mating opportunities, males that quickly ascend the hierarchy may benefit from eliminating the dependent offspring of their competitors. In savanna baboons, high-ranking females are the most profitable targets of infanticide or feticide, because their offspring have higher survival rates and their daughters reach sexual maturity at a younger age. However, such patterns may be obscured by environmental stressors that are known to exacerbate fetal losses, especially in lower-ranking females. Using 30 years of data on wild olive baboons (Papio anubis) in Gombe National Park, Tanzania, we found evidence that rapidly-rising immigrant males induced miscarriages in high-ranking females outside of drought conditions. However, miscarriage rates were largely reversed during prolonged periods of low rainfall, suggesting that low-ranking females are particularly vulnerable to low food availability and social instability. Infanticide did not emerge as a recurrent male strategy in this population, likely because of the protective behavior of resident males towards vulnerable juveniles.
在哺乳动物中，雌性通常会对后代进行长时间的投资，而雄性中地位较高的个体往往拥有更多的交配机会。因此，那些能够迅速提升社会等级的雄性可能会受益于消灭竞争对手的后代。在草原狒狒中，高等级的雌性是杀婴或流产的最主要目标，因为它们的后代存活率更高，而且其女儿性成熟的年龄也更早。然而，环境压力可能会掩盖这种模式，已知环境压力会加剧胎儿的损失，尤其是在低等级的雌性中。本研究利用了坦桑尼亚贡贝国家公园野生橄榄狒狒（Papio anubis）长达 30 年的数据，发现证据表明，在没有干旱的情况下，快速崛起的移民雄性会导致高等级雌性流产。然而，在长时间低降雨量的情况下，流产率在很大程度上被逆转，这表明低等级的雌性特别容易受到食物短缺和社会不稳定的影响。在这个种群中，杀婴并没有成为雄性的一种常见策略，这可能是因为居留雄性会对脆弱的幼崽采取保护行为。
