Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?

Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?

One of nature's premier illustrations of adaptive evolution concerns the tight correspondence in birds between beak morphology and feeding behavior. In seed-crushing birds, beaks have been suggested to evolve at least in part to avoid fracture. Yet, we know little about mechanical relationships...

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Main Authors: Soons, Joris, Genbrugge, Annelies, Podos, Jeffrey, Adriaens, Dominique, Aerts, Peter, Dirckx, Joris, Herrel, Anthony
Format: Online
Language:English
Published: Public Library of Science 2015
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466803/
id pubmed-4466803
recordtype oai_dc
spelling pubmed-44668032015-06-22 Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands? Soons, Joris Genbrugge, Annelies Podos, Jeffrey Adriaens, Dominique Aerts, Peter Dirckx, Joris Herrel, Anthony Research Article One of nature's premier illustrations of adaptive evolution concerns the tight correspondence in birds between beak morphology and feeding behavior. In seed-crushing birds, beaks have been suggested to evolve at least in part to avoid fracture. Yet, we know little about mechanical relationships between beak shape, stress dissipation, and fracture avoidance. This study tests these relationships for Darwin's finches, a clade of birds renowned for their diversity in beak form and function. We obtained anatomical data from micro-CT scans and dissections, which in turn informed the construction of finite element models of the bony beak and rhamphotheca. Our models offer two new insights. First, engineering safety factors are found to range between 1 and 2.5 under natural loading conditions, with the lowest safety factors being observed in species with the highest bite forces. Second, size-scaled finite element (FE) models reveal a correspondence between inferred beak loading profiles and observed feeding strategies (e.g. edge-crushing versus tip-biting), with safety factors decreasing for base-crushers biting at the beak tip. Additionally, we identify significant correlations between safety factors, keratin thickness at bite locations, and beak aspect ratio (depth versus length). These lines of evidence together suggest that beak shape indeed evolves to resist feeding forces. Public Library of Science 2015-06-12 /pmc/articles/PMC4466803/ /pubmed/26068929 http://dx.doi.org/10.1371/journal.pone.0129479 Text en © 2015 Soons et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
repository_type Open Access Journal
institution_category Foreign Institution
institution US National Center for Biotechnology Information
building NCBI PubMed
collection Online Access
language English
format Online
author Soons, Joris
Genbrugge, Annelies
Podos, Jeffrey
Adriaens, Dominique
Aerts, Peter
Dirckx, Joris
Herrel, Anthony
spellingShingle Soons, Joris
Genbrugge, Annelies
Podos, Jeffrey
Adriaens, Dominique
Aerts, Peter
Dirckx, Joris
Herrel, Anthony
Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
author_facet Soons, Joris
Genbrugge, Annelies
Podos, Jeffrey
Adriaens, Dominique
Aerts, Peter
Dirckx, Joris
Herrel, Anthony
author_sort Soons, Joris
title Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
title_short Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
title_full Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
title_fullStr Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
title_full_unstemmed Is Beak Morphology in Darwin’s Finches Tuned to Loading Demands?
title_sort is beak morphology in darwin’s finches tuned to loading demands?
description One of nature's premier illustrations of adaptive evolution concerns the tight correspondence in birds between beak morphology and feeding behavior. In seed-crushing birds, beaks have been suggested to evolve at least in part to avoid fracture. Yet, we know little about mechanical relationships between beak shape, stress dissipation, and fracture avoidance. This study tests these relationships for Darwin's finches, a clade of birds renowned for their diversity in beak form and function. We obtained anatomical data from micro-CT scans and dissections, which in turn informed the construction of finite element models of the bony beak and rhamphotheca. Our models offer two new insights. First, engineering safety factors are found to range between 1 and 2.5 under natural loading conditions, with the lowest safety factors being observed in species with the highest bite forces. Second, size-scaled finite element (FE) models reveal a correspondence between inferred beak loading profiles and observed feeding strategies (e.g. edge-crushing versus tip-biting), with safety factors decreasing for base-crushers biting at the beak tip. Additionally, we identify significant correlations between safety factors, keratin thickness at bite locations, and beak aspect ratio (depth versus length). These lines of evidence together suggest that beak shape indeed evolves to resist feeding forces.
publisher Public Library of Science
publishDate 2015
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466803/
_version_ 1613235538158944256

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