Mendl M
Department of Clinical Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 OES, UK.
Behav Processes. 1994 Apr;31(2-3):285-91. doi: 10.1016/0376-6357(94)90013-2.
Although natural selection may favour the evolution of an optimal brood size, unpredictable environmental factors can intervene to render the brood either considerably larger or smaller than this optimum. The question therefore arises as to how parents should respond to unusually large or small litters. Solutions to this problem which involve abandonment of the offspring or brood reduction, for example by infanticide, have received most theoretical and empirical attention. For small mammalian litters, however, evidence that parents employ these behavioural strategies is sparse. I suggest that, under certain conditions, an alternative to abandonment and infanticide of small litters in mammals is an increase in total parental care above that seen in larger litters. Evidence is presented which supports this possibility. This strategy may allow parents to compensate for the loss of offspring by producing a small number of high quality individuals. It is most likely to occur when opportunities for rapid rebreeding are limited, and when increases in parental care have strong effects on offspring quality. Interest in abandonment and infanticide has diverted attention away from this alternative parental response to small litters. Studies of this response are encourage, not least because they will focus attention on the poorly understood relationship between parental care and offspring quality.
尽管自然选择可能有利于最优窝卵数的进化，但不可预测的环境因素可能会介入，使窝卵数比这个最优值大得多或小得多。因此就产生了一个问题，即父母应该如何应对异常大或小的窝仔数。涉及抛弃后代或减少窝仔数（例如通过杀婴）的解决这个问题的方法受到了最多的理论和实证关注。然而，对于小型哺乳动物的窝仔数，父母采用这些行为策略的证据很少。我认为，在某些情况下，哺乳动物抛弃和杀婴小型窝仔数的替代方法是增加总的亲代抚育，超过在较大窝仔数情况下的抚育水平。文中给出了支持这种可能性的证据。这种策略可能使父母通过生育少量高质量个体来弥补后代的损失。当快速再次繁殖的机会有限，且亲代抚育的增加对后代质量有强烈影响时，这种情况最有可能发生。对抛弃和杀婴的关注转移了人们对这种亲代对小型窝仔数的替代反应的注意力。鼓励对这种反应进行研究，尤其是因为它们将把注意力集中在亲代抚育与后代质量之间 poorly understood 的关系上。 （注：原文中“poorly understood”直译为“理解不充分的”，这里意译为“了解甚少的”更通顺些）
