Counter-Strategies against Infanticide by Males in Primates

雄性杀婴，即成年雄性瞄准、攻击和杀害脆弱的婴儿，发生在广泛的哺乳动物中，一个重要的研究机构调查了这些雄性如何从杀害婴儿中获益。然而，杀害男婴对其他三个人--母亲、婴儿和父亲--来说代价高昂，而且人们对他们如何应对杀婴风险知之甚少。我之前曾研究过雌性动物抵抗或应对野生灵长类动物(黑白鳞甲)杀婴风险所使用的策略。高杀婴风险对婴儿和父亲的影响，以及他们如何制定策略来抵制杀婴，受到的研究关注要少得多。我的目标是继续测试与雌性应对策略被雄性杀害婴儿相关的假设，并扩大调查范围，以包括与相同种群的野生结肠猴的婴儿和父亲的成本和应对策略相关的假设的测试。该种群种群密度高，雄性交配竞争激烈，雄性杀婴事件时有发生。个人因所在群体的不同而经历不同程度的杀婴风险，因为常住男性(S)的父子关系概率不同，从一男多妻(高父权概率)、稳定的多男多妻群体(中等父权概率)，到最近发生接管且新居民男性(S)在受孕前后没有与女性交配(低父子概率)的群体。这些条件(高人口密度、高男性交配竞争、不同社会群体的不同杀婴风险)创造了收集检验研究假设所需数据的理想环境。我和我的学生将进行多项研究，以检验以下假设：在高杀婴风险条件下，母亲会突然断奶，并会与几个男性交配，以传播父子关系的概率；仍然在高杀婴风险条件下，婴儿发育将加速，这种更快的婴儿发育将转化为更早的营养独立；父亲对婴儿的耐受性将受到父亲身份的影响，并将随杀婴风险水平的不同而变化。已经进行了大量研究，以了解发生男婴杀戮的条件，以及了解杀婴男性如何从这种行为的表现中获益。这项研究有助于我们了解这场进化军备竞赛的另一面，评估母亲、婴儿和父亲--对他们来说，杀害男婴代价高昂--为应对杀害男婴的威胁而采取的策略。

Infanticide by males, where adult males target, attack and kill vulnerable infants, occurs in a wide range of mammals, and an important body of research investigates how these males gain from killing infants. Male infanticide is costly, however, for three other individuals - the mother, the infant and the father and much less is known about how they cope with the risk of infanticide. I have previously investigated the tactics used by females to resist or cope with infanticide risk in a wild primate species (the black and white colobus). The impact of high infanticide risk on infants and fathers, and how they might develop tactics to resist infanticide, has received much less research attention. My objective is to continue to test hypotheses related to female counterstrategies infanticide by males, and to extend the investigation to include the testing of hypotheses related to the costs to, and counter-strategies employed by, infants and fathers, with the same population of wild colobus monkeys. This population has high population density and intense male mating competition, and infanticide by males occurs regularly. Individuals experience varying levels of infanticide risk depending on the group in which they live, since paternity probability for resident male(s) varies from uni-male, polygynous groups (high paternity probability), stable multi-male, polygynandrous groups (moderate level of paternity probability) to groups where a recent takeover occurred and where the new resident male(s) did not mate with the females around the time of conception (low paternity probability). These conditions (high population density, high male mating competition, varying infanticide risk depending on the social groups) create an ideal situation in which to collect the data necessary to test the research hypotheses. My students and I will conduct a number of studies to test the following hypotheses: Under high infanticide risk conditions, mothers will wean their infant abruptly, and will mate with several males to spread paternity probabilities; still under high infanticide risk conditions, infant development will be accelerated and this faster infant development will translate into earlier nutritional independence; and fathers' tolerance of infants will be influenced by paternity and will co-vary with the level of infanticide risk. Considerable research has been conducted to understand the conditions under which male infanticide occurs, as well as to understand how infanticidal males might gain from the expression of this behaviour. This study contributes to our understanding of the other side of this evolutionary arms race, in assessing the strategies used by mothers, infants and fathers - for whom male infanticide is costly - to cope with the threat of male infanticide.