Abstract Detail



Macroevolution

Lemenager, Marion [1], Clark, John L. [2], Martén-Rodríguez, Silvana [3], Almarales-Castro, Abel [4], Joly, Simon [5].

Evolution and intraspecific variation of corolla morphologies in association with pollination strategies.

Pollinators are important selective agents shaping floral morphology. The identity of pollinators has indeed long been known to affect the strength and directionality of floral evolution and floral phenotypic variation. But the width of the pollination niche can also impact morphological variation. Pollination specialists, pollinated by a single or few functionally similar species, are expected to be under relatively constant selection pressure and as such exhibit less phenotypic variation than generalist. This is because generalists, pollinated by several functional types of pollinators, have been proposed to have either wider niche ranges than specialists in terms of pollinators, or to be composed of an heterogeneous set of individuals each relatively specialized to a few pollinators, but overall having a wider range of visiting pollinators than specialists. Generalists are thus expected to be more intra-specifically variable than specialists in their floral shapes as a result of multiple contradicting selective pressures imposed by the different functional types of acting pollinators. Hence the question : is the relative degree of morphological variation in floral shape predictable according to the degree of pollination specialisation ? Specialist as well as generalist pollination strategies can be distinguished in the Gesneriaceae family from the West Indies. Interacting with hummingbirds, bats, and insects, independently or jointly to ensure their pollination, they display a wide variety of floral morphologies. Using this group, we test if pollination generalists have greater intra-specific variation of their corolla shape compared to specialists. To test this hypothesis, we quantified corolla shapes from profiles using geometric morphometrics and compared the infraspecific variation of species in a phylogenetic comparative analysis integrating a hierarchical bayesian framework. We found that in most aspects of the corolla morphology, generalists do have a larger intra-specific variation than specialists. The greater variation of pollination generalist supports our hypothesis, but whether this is the results of greater variation overall or of the presence of many diversified specialized phenotypes will have to be investigated in a further study.


1 - Institut de recherche en biologie vegetale, 4101 Sherbrooke East, Montreal, QC, H1X2B2, Canada
2 - University of Alabama, Science and Engineering Complex, 1325 Hackberry Ln, Tuscaloosa, AL, 35401, USA
3 - Universidad Nacional Autónoma de México, Escuela Nacional de Estudios Superiores-Unidad Morelia, Antigua Carretera a Pátzcuaro 8701, Sin Nombre, Indeco la Huerta, Michoacán, 58190, Mexico
4 - Centro Oriental de Ecosistemas y Biodiversidad (Bioeco), Santiago de Cuba, Cuba
5 - Montreal Botanical Garden, 4101 Sherbrooke East, Montreal, QC, H1X 2B2, Canada

Keywords:
morphology
Generalist pollination systems
instraspecific variation
Shape evolution
Specialist pollination systems.

Presentation Type: Oral Paper
Number: MACRO2005
Abstract ID:675
Candidate for Awards:None


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