Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Diagonal Las Torres 2640, Santiago, Chile.
Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
Ecol Lett. 2019 Jan;22(1):128-137. doi: 10.1111/ele.13174.
Individual diet specialisation (IS) is frequent in many animal taxa and affects population and community dynamics. The niche variation hypothesis (NVH) predicts that broader population niches should exhibit greater IS than populations with narrower niches, and most studies that examine the ecological factors driving IS focus on intraspecific competition. We show that phenotypic plasticity of traits associated with functional trade-offs is an important, but unrecognised mechanism that promotes and maintains IS. We measured nitrogen isotope (δ N) and digestive enzyme plasticity in four populations of sparrows (Zonotrichia capensis) to explore the relationship between IS and digestive plasticity. Our results show that phenotypic plasticity associated with functional trade-offs is related in a nonlinear fashion with the degree of IS and positively with population niche width. These findings are opposite to the NVH and suggest that among individual differences in diet can be maintained via acclimatisation and not necessarily require a genetic component.
个体饮食特化（IS）在许多动物类群中很常见，会影响种群和群落动态。生态位变异假说（NVH）预测，具有较宽生态位的种群应该比具有较窄生态位的种群表现出更大的 IS，而大多数研究关注的是驱动 IS 的种内竞争的生态因素。我们表明，与功能权衡相关的性状表型可塑性是促进和维持 IS 的一个重要但未被认识的机制。我们测量了四种雀类（Zonotrichia capensis）的氮同位素（δN）和消化酶可塑性，以探索 IS 与消化可塑性之间的关系。我们的结果表明，与功能权衡相关的表型可塑性与 IS 的程度呈非线性关系，并与种群生态位宽度呈正相关。这些发现与 NVH 相反，表明饮食个体差异可以通过适应来维持，而不一定需要遗传成分。
