The diets of individual animals within populations can differ, but few studies determine whether this is due to fundamental differences in preferences or capacities to eat specific foods, or to external influences such as dominance hierarchies or spatial variation in food availability. The distinction is important because different drivers of dietary specialisation are likely to have different impacts on the way in which animal populations respond to, for example, habitat modification. We used a captive feeding study to investigate the mechanisms driving individual dietary specialisation in a population of wild koalas (Phascolarctos cinereus) in which individuals predominantly ate either Eucalyptus viminalis or Eucalyptus obliqua foliage. All six koalas that primarily ate E. viminalis in the wild avoided eating E. obliqua for more than 1 month in captivity. In contrast, all seven koalas that primarily ate E. obliqua could be maintained exclusively on this species in captivity, although they ate less from individual trees with higher foliar concentrations of unsubstituted B-ring flavanones (UBFs). Our results show that fundamental differences between individual animals allow some to exploit food resources that are less suitable for others. This could reduce competition for food, increase habitat carrying capacity, and is also likely to buffer the population against extinction in the face of habitat modification. The occurrence of fundamental individual specialisation within animal populations could also affect the perceived conservation value of different habitats, translocation or reintroduction success, and population dynamics. It should therefore be further investigated in other mammalian herbivore species.

种群内个别动物的饮食可能不同，但很少有研究确定这是否是由于偏好或食用特定食物的能力的根本差异，还是由于优势等级或食物可用性的空间变化等外部影响。这种区别很重要，因为饮食专业化的不同驱动因素可能会对动物种群的反应方式产生不同的影响，例如栖息地改变。我们使用圈养喂养研究来调查野生考拉 ( Phascolarctos cinereus )种群中驱动个体饮食专业化的机制，其中个体主要食用Eucalyptus viminalis或Eucalyptusobliqua 。叶子。在野外主要吃E. viminalis 的所有 6 只考拉在被圈养的 1 个多月内都避免吃E.obliqua。相比之下，主要吃E.obliqua 的所有七只考拉可以在圈养中仅在该物种上维持，尽管它们从具有较高叶面浓度的未取代 B 环黄烷酮 (UBF) 的个体树木中摄取较少。我们的研究结果表明，个体动物之间的根本差异允许一些动物利用不太适合其他动物的食物资源。这可以减少对食物的竞争，增加栖息地承载能力，并且还可能在栖息地改变时缓冲人口免于灭绝。动物种群中基本个体专业化的发生也可能影响不同栖息地的感知保护价值、易地或重新引入的成功以及种群动态。因此，应该在其他哺乳动物食草动物物种中进一步研究。