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Form and function in the bills of cavity-excavating barbets

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dc.contributor.advisor Krishnan, Anand en_US
dc.contributor.author CHHAYA, VAIBHAV en_US
dc.date.accessioned 2022-05-06T05:14:48Z
dc.date.available 2022-05-06T05:14:48Z
dc.date.issued 2022-05
dc.identifier.citation 66 en_US
dc.identifier.uri http://dr.iiserpune.ac.in:8080/xmlui/handle/123456789/6797
dc.description.abstract The patterns and processes underlying morphological diversification are strongly influenced by the functional requirements of organisms. Bird bills are structurally and functionally diverse, and are uniquely suited to study form-function relationships. When birds use their bills to excavate nesting cavities, physical stresses experienced by the bill during nest excavation may be linked to bill shape and material composition. This relationship is affected by broad environmental factors like climate, which influences the mechanical properties of available substrates, as well as proximate factors like stress dissipation by the bill structure. This thesis explores the patterns, drivers, and biomechanical consequences of bill shape diversification in barbets, a group of nest-excavating frugivorous birds. First, we used geometric morphometrics to quantify bill shape variation and investigate the patterns and ecological drivers of shape for four components of the bill- the outer rhamphotheca and the inner bony core of the upper and lower mandibles. Next, we evaluated the excavation performance of different bill shapes and material compositions using finite element analysis and beam theory. We find that bill shape diversity has gradually accumulated over time across the two lineages, with maxillary shape driven by climate and allometry. Maxillary geometry is strongly linked to excavation performance, with deeper and wider bills exhibiting higher impact resistance and narrower bills exhibiting higher torsion resistance. In addition, the rhamphotheca and bony modules of the upper and lower mandibles have evolved as a single functional unit, and have a synergistic effect on stress dissipation. Through these findings, our integrative study sheds light on the evolution of structural and functional diversity in birds. en_US
dc.description.sponsorship Kishore Vaigyanik Protsahan Yojana (KVPY) fellowship, Department of Science and Technology (DST), Government of India; INSPIRE Faculty Award, Department of Science and Technology (DST), Government of India; Early Career Research Grant (ECR/2017/001527), Science and Engineering Research Board (SERB), Government of India en_US
dc.language.iso en_US en_US
dc.subject birds en_US
dc.subject morphological evolution en_US
dc.subject barbets en_US
dc.subject geometric morphometrics en_US
dc.subject finite element analysis en_US
dc.subject computed tomography en_US
dc.subject phylogenetic comparative methods en_US
dc.subject cavity excavation en_US
dc.subject beak shape en_US
dc.subject comparative biomechanics en_US
dc.title Form and function in the bills of cavity-excavating barbets en_US
dc.type Thesis en_US
dc.type.degree BS-MS en_US
dc.contributor.department Dept. of Biology en_US
dc.contributor.registration 20171136 en_US


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  • MS THESES [1713]
    Thesis submitted to IISER Pune in partial fulfilment of the requirements for the BS-MS Dual Degree Programme/MSc. Programme/MS-Exit Programme

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