Ecological drivers of song evolution in birds: Disentangling the effects of habitat and morphology

Abstract

Environmental differences influence the evolutionary divergence of mating signals through selection acting either directly on signal transmission (“sensory drive”) or because morphological adaptation to different foraging niches causes divergence in “magic traits” associated with signal production, thus indirectly driving signal evolution. Sensory drive and magic traits both contribute to variation in signal structure, yet we have limited understanding of the relative role of these direct and indirect processes during signal evolution. Using phylogenetic analyses across 276 species of ovenbirds (Aves: Furnariidae), we compared the extent to which song evolution was related to the direct influence of habitat characteristics and the indirect effect of body size and beak size, two potential magic traits in birds. We find that indirect ecological selection, via diversification in putative magic traits, explains variation in temporal, spectral, and performance features of song. Body size influences song frequency, whereas beak size limits temporal and performance components of song. In comparison, direct ecological selection has weaker and more limited effects on song structure. Our results illustrate the importance of considering multiple deterministic processes in the evolution of mating signals.

Vocal divergence between two disjunct populations of Giant Antshrike (Batara cinerea) is related to environmental conditions

“…A similar condition was found in Ovenbirds (Furnariidae), where Derryberry et al . () found temporal variation among species emerging from both direct selection via environmental absorption and indirect selection via morphological traits, while spectral variation was mainly influenced by morphology.…”

Habitat structure drives the evolution of aerial displays in birds

“…It is also the first phylogenetic analysis to find evidence of habitat shaping the evolution of gestural displays. Previous studies had recognized the role of habitat structure in shaping sound-, colour-and ornament-based signals in lizards and birds 42–47 , but failed to detect an influence of habitat on the structure of motion-based signals ( e.g., in fiddler crabs 16 ). More than seven decades after Armstrong’s 34 (p. 247) remark that “high-flying […] displays are most characteristic of birds of the open country”, we offer compelling evidence of the evolutionary process that likely underlies this pattern.…”

Environmental and morphological constraints interact to drive the evolution of communication signals in frogs

“…Environmentally-dependent selection pressures can operate in any of these three processes, with important consequences for signal evolution. In the case of acoustic signals, several studies have investigated the role of variation in transmission environment as a driving factor of signal evolution (e.g., Richards & Wiley 1980; Peters & Peters 2010; García-Navas & Blumstein 2016; Derryberry et al 2018). During transmission, sound signals will experience changes in their temporal and spectral properties (Bradbury & Vehrencamp 2011), which can affect the capacity of receivers to process these signals.…”