Ecophysical constraints on avian adaptation and diversification
File(s)
Accepted version
Author(s)
Sayol, Ferran
Reijenga, Bouwe R
Tobias, Joseph A
Pigot, Alex L
Type
Journal Article
Abstract
The evolution of morphological diversity is ultimately governed by physical laws and ecological contexts, which together impose a range of ecophysical constraints. Substantial progress has been made in identifying how these constraints shape the form and function of producers (plants), but similar knowledge is lacking for consumers, in part because the requisite data have not been available at sufficient scale for animals. Using morphometric measurements for all birds, we demonstrate that observed variation is restricted—both for beak shape and body shape—to triangular regions of morphospace with clearly defined boundaries and vertices (corners). By combining morphometric data with information on ecological and behavioral functions, we provide evidence that the extent of avian morphospace reflects a trade-off between three fundamental physical tasks for feeding (crush, engulf, and reach) that characterize resource acquisition and processing by the beak and three physical tasks (fly, swim, and walk) that characterize avian lifestyles or locomotion. Phylogenetic analyses suggest that trajectories of morphological evolution trend toward the vertices, with lineages evolving from a core of functional generalists toward more specialized physical tasks. We further propose that expansion beyond the current boundaries of morphospace is constrained by the shorter evolutionary lifespan of functional specialists, although patterns of speciation rate and current extinction risk provide only weak support for this hypothesis. Overall, we show that the structure of avian morphospace follows relatively simple rules defined by ecophysical constraints and trade-offs, shedding light on the processes shaping modern animal diversity and responses to environmental change.
Date Issued
2025-03-24
Date Acceptance
2025-02-07
Citation
Current Biology, 2025, 35 (6), pp.1326-1336.e6
ISSN
0960-9822
Publisher
Elsevier BV
Start Page
1326
End Page
1336.e6
Journal / Book Title
Current Biology
Volume
35
Issue
6
Copyright Statement
© 2025 Elsevier Inc. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/40043700
PII: S0960-9822(25)00149-6
Subjects
Pareto optimization
birds
ecological function
ecomorphology
extinction
functional traits
morphospace
niche evolution
specialization
trade-offs
Animals
Birds
Biological Evolution
Phylogeny
Beak
Adaptation, Physiological
Biodiversity
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2025-03-04