Thesis
Reproductive character displacement shapes a spatially structured petal color polymorphism in Leavenworthia stylosa
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/102299
Abstract
Character displacement, or selection to reduce costly interspecific interactions, is a potentially important force driving trait evolution and the diversification of species. Floral traits may experience character displacement if they relax pollinator-mediated competition (ecological character displacement) or prohibit the formation of hybrids with reduced fitness (reproductive character displacement). We test these and alternative hypotheses to explain a yellow-white petal color polymorphism in Leavenworthia stylosa, where yellow morphs are spatially associated with a white-petaled congener (L. exigua) that produces hybrids with complete pollen sterility. A reciprocal transplant experiment rejected the hypothesis of local adaptation of color morphs, and a pollen limitation experiment showed that yellow petals do not alleviate competition for pollination. Pollinator observations revealed that Leavenworthia attracts a variety of pollinators that generally favor white petals and exhibit color constancy. Pollinator movements between species were infrequent and low maximum likelihood estimates of hybridization rates (~0.45% - 0.97%) were found in pooled DNA in each morph. Consistent with patterns of pollinator movement, hybridization rates were significantly higher in white morphs of L. stylosa, yielding a selection coefficient of s = 0.005 against this phenotype in sympatry with L. exigua. These v results provide support for reproductive character displacement as a mechanism contributing to the pattern of petal color polymorphism in L. stylosa.
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Details
- Title
- Reproductive character displacement shapes a spatially structured petal color polymorphism in Leavenworthia stylosa
- Creators
- Nicholas Andrew Norton
- Contributors
- Jeremiah W. Busch (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525145001842
- Language
- English
- Resource Type
- Thesis