UMR-5174, EDB, CNRS, Université Toulouse III-Paul Sabatier, IRD, Toulouse, France.
UMR RECOVER, INRAE, Aix Marseille Univ, Aix-en-Provence, France.
Ecol Lett. 2020 Aug;23(8):1242-1251. doi: 10.1111/ele.13528. Epub 2020 May 11.
Trophic cascades - the indirect effect of predators on non-adjacent lower trophic levels - are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying ecological networks. Here we experimentally investigated how intraspecific difference among herbivore lineages specialized on different host plants influences trophic cascade strength in a terrestrial tri-trophic system. We found that the occurrence and strength of the trophic cascade are strongly influenced by herbivores' lineage and host-plant specialization but are not associated with density-dependent effects mediated by the growth rate of herbivore populations. Our findings stress the importance of intraspecific heterogeneities and evolutionary specialization as drivers of trophic cascade strength and underline that intraspecific variation should not be overlooked to decipher the joint influence of evolutionary and ecological factors on the functioning of multi-trophic interactions.
营养级联——捕食者对非相邻下营养级的间接影响——是生态群落结构和动态的重要驱动因素。然而，种内特征变异对营养级联强度的影响在很大程度上仍未得到探索，这限制了我们对生态网络潜在机制的理解。在这里，我们通过实验研究了专门以不同宿主植物为食的食草动物谱系之间的种内差异如何影响陆地三营养级系统中的营养级联强度。我们发现，营养级联的发生和强度强烈受食草动物谱系和宿主植物专化性的影响，但与由食草动物种群增长率介导的密度依赖性效应无关。我们的研究结果强调了种内异质性和进化特化作为营养级联强度驱动因素的重要性，并强调不应忽视种内变异，以揭示进化和生态因素对多营养级相互作用功能的共同影响。
