Socioecology of Infanticide in White-Footed Mice

杀婴，即同一物种的其他成员杀死婴儿，在野生动物中是一种普遍现象。成年雄性经常杀死不相关的幼崽，然后与雌性交配，而成年雌性杀死陌生的幼崽，以消除对后代的竞争，并获得受害雌性的巢穴。关于杀婴行为发生的条件、雄性和雌性用来区分自己与无关后代的机制、杀婴行为如何影响人口增长、以及杀婴倾向是否遗传，人们知之甚少。在这项拟议的研究中，首席研究员将确定(1)雄性和雌性使用什么线索来识别自己的后代，从而避免杀死相关的幼崽；(2)是否存在杀婴倾向的遗传基础；(3)杀婴动物和非杀婴动物的存在如何影响种群的增长和稳定。研究人员将对有标记的野生白足鼠种群在高密度和低密度下的杀婴频率进行监测，并在实验室进行繁殖实验，以确定杀婴行为的遗传。首席研究员之前的研究表明，大约50%的动物是杀婴的，50%的动物不是杀婴的。杀婴和不杀婴的动物将被引入不同的围栏，以确定杀婴行为对社会互动和种群增长的影响。研究结果将表明，一种看似病态的行为实际上是如何适应并在种群中传播的。这也将阐明雌性攻击性作为一种保护幼崽免受同类侵害的机制的重要性。

Infanticide, the killing of infants by other members of the same species, is a common phenomenon in wild animals. Adult males often kill unrelated infants and then mate with the female, whereas adult females kill strange pups to remove competition for their offspring and to acquire the nest of the victim female. Little is known about the conditions under which infanticide occurs, the mechanisms males and females use to distinguish their own from unrelated offspring, how infanticide affects population growth, and whether or not the tendency to commit infanticide is inherited. In this proposed study the principal investigator will determine (1) what cues males and females use to recognize their own offspring, and thus avoid killing related pups, (2) if there is genetic basis for the tendency to commit infanticide, and (3) how population growth and stability are affected by the presence of infanticidal and noninfanticidal animals. The frequency of infanticide in a marked, wild population of white- footed mice at high and low densities will be monitored, and breeding experiments will be conducted in the laboratory to determine the inheritance of infanticidal behavior. Previous studies by the Principal Investigator have shown that about 50% of the animals are infanticidal and 50% are noninfanticidal. Infanticidal and noninfanticidal animals will be introduced to different enclosures to determine the effects of infanticide on social interactions and population growth. The results will show how a seemingly pathological behavior can actually be adaptive and spread through a population. It will also shed light on the significance of female aggression as a mechanism to protect her pups from other members of her own species.