KÖLLIKER M, Richner H, Werner I, Heeb P
Zoology Department, University of Bern
Anim Behav. 1998 Jan;55(1):215-22. doi: 10.1006/anbe.1997.0571.
The evolutionary conflict over the amount of resources transferred between a parent and its offspring may be resolved by honest signalling of 'need' by offspring and parental investment in relation to signalling level. In birds, biparental care is the norm and evidence that male and female parents differ in their investment pattern in individual offspring is growing. In an experiment on great tits, Parus major, we investigated how and why parents differ in food allocation when responding to similar chick signals, which supposedly uniquely reflect the chick's nutritional condition. Nestling hunger level was manipulated by food deprivation and hand-feeding. Subsequent filming revealed that parents fed from significantly different locations on the nest and thereby forced chicks to choose between them when competing for favourable positions. Deprived nestlings approached, and fed ones retreated (or were displaced by siblings) from, positions near the female. No such behaviour was observed towards the male. Females allocated more feeds than males to the food-deprived nestlings. The results are discussed in terms of nestling competition for access to 'begging patches'. By varying their 'begging patch' value, parents may exploit competitive inter-sibling dynamics to influence the outcome of competition among chick phenotypes (e.g. 'need', size, sex). Parent birds may thereby exert considerable control over the information content of chick begging behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.
亲代与子代之间关于资源转移量的进化冲突，可能通过子代诚实地发出“需求”信号以及亲代根据信号水平进行投资来解决。在鸟类中，双亲共同育雏是常态，而且有越来越多的证据表明，雄性和雌性亲代在对单个子代的投资模式上存在差异。在一项针对大山雀（Parus major）的实验中，我们研究了亲代在对相似的雏鸟信号做出反应时，食物分配方式为何不同以及存在差异的原因，这些信号理应唯一地反映了雏鸟的营养状况。通过食物剥夺和人工喂养来控制雏鸟的饥饿程度。随后的拍摄显示，亲代在巢中从显著不同的位置喂食，从而迫使雏鸟在争夺有利位置时在它们之间做出选择。饥饿的雏鸟会靠近雌性附近的位置，而已经喂过食的雏鸟（或被兄弟姐妹挤到一边）则会从这些位置退开。对于雄性亲代则未观察到这种行为。雌性亲代给饥饿的雏鸟分配的食物比雄性亲代更多。我们从雏鸟对“乞食区域”的竞争角度对这些结果进行了讨论。通过改变它们“乞食区域”的价值，亲代可能利用兄弟姐妹间的竞争动态来影响雏鸟不同表型（如“需求”、体型、性别）之间竞争的结果。亲鸟可能因此对雏鸟乞食行为的信息内容施加相当大的控制。版权所有1998动物行为研究协会。
