Mimicry as a novel pathway linking biodiversity functions and individual behavioural performances.

The feedback of biodiversity on individual trait variation is a poorly explored mechanistic pathway in ecological research. We analysed the relationship between biodiversity and individual performance by focusing on vocal mimicry, a widespread interaction that may serve in intra- and interspecific communication. We studied the songs of two lark species (genus Galerida) that increase the complexity of their song displays by mimicking other birds, and analysed the influence of bird species richness on individual song performance. The diversity of mimicked species and the prevalence of mimicry increased in areas characterized by great α and γ diversity (i.e. where larks experience more diverse encounters with community members, many of them being highly vocal owing to breeding). Conversely, the variability in species-specific song components peaked where larks were abundant, probably matching the complexity of conspecific social milieu. Some trade-offs existed between homo- and heterospecific complexity, suggesting that larks could change from population- to community-driven song variation by tracking the composition of the auditory environment. Mimicry, which serves communication with conspecifics or predators, may mediate interactions, ultimately cascading to aspects of ecological diversity other than those promoting its complexity.