Salvato in:
| Autore principale: | |
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| Natura: | Recurso digital |
| Lingua: | |
| Pubblicazione: |
Zenodo
1981
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| Soggetti: | |
| Accesso online: | https://doi.org/10.5281/zenodo.13413108 |
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Sommario:
- (Uploaded by Plazi for the Bat Literature Project) The overallobjectiveis to comparethe ecologicalimpactof bird-flowercoevolutionin different geographicalareas. However, it is first necessary to define the parametersof such coevolutionin broadertermsthanthose of the traditional"syndromeof ornithophily,"whichfocuses very narrowly on some aspects of floral morphology.I recognize three distinct componentsof flower function: attraction,reward,andfilteringmechanisms,and discuss theirfunctioningin an ecologicalcontext, and as they relate to the genetic system or "pollinationunit" of the plant. Then I turnto nectarfeeding birds, and discuss not only morphological,but ecological and behavioralspecializationsto flowersas a food source.Thesediscussionsdevelopexplicitlymy criteriafor detectingandevaluating bird-flowercoevolution.The differentgroupsof birdsknownto feed regularly(as opposedto opportunistically)on nectar are then comparedaccordingto these criteria,to determinetheir relative degreesof specializationfor, anddependenceupon, a high-nectardiet. Differentgroupsarefoundto vary widely in their degrees of specializationfor flower-feeding,and it is evident that bird-flower coevolution has followed very differentcourses, and led to widely divergentecological systems in differentgeographicalareas. By any criteriathe hummingbirdsare the most specializedavian nectarivores,althoughthey are approachedin this regardby some membersof certainpasserinegroups, notablyamongthe sunbirds.Severalgroupsof passerinenectarivoresalso occur with the hummingbirds in many New Worldareas;these groups show low to moderatedegreesof specializationfor nectarivory,eitheras pollinatorsor as parasiteson the hummingbird-flowesrystem. The New World tropicsthuspresenta widerangeof specializationsfor flower-feedingin theiravifauna,andrepresent a particularlyinterestingareafor study. Patternsof ornithophilyand nectarivoryare thus examined in detailfor this area,concentratingspecificallyon SouthernCentralAmerica,especiallyCostaRica.