Reproductive character displacement shapes a spatially structured petal color polymorphism inLeavenworthia stylosa

• DOI: 10.1111/evo.12659
• Publication Date: 2015-04-15T06:09:20Z
• Authors: Nicholas A. Norton; M. Thilina R. Fer...; Christopher R. He...; Jeremiah W. Busch
• Keywords: Character displacement; Petal; Reproductive isolation; Reciprocal cross

Character displacement is a potentially important process driving trait evolution and species diversification. Floral traits may experience character in response to pollinator-mediated competition (ecological displacement) or the risk of forming hybrids with reduced fitness (reproductive displacement). We test these alternative hypotheses explain yellow-white petal color polymorphism Leavenworthia stylosa, where yellow morphs are spatially associated white-petaled congener (Leavenworthia exigua) that produces complete pollen sterility. A reciprocal transplant experiment found limited evidence local adaptation via increased survival seed set. Pollinator observations revealed attract various pollinators generally favor white petals exhibit constancy. Pollen limitation experiments showed do not alleviate for pollination. Interspecific pollinator movements were infrequent low hybridization rates (∼0.40-0.85%) each morph, natural likely being lower. Regardless, significantly higher L. yielding small selection coefficient s = 0.0042 against this phenotype sympatry exigua. These results provide support RCD as mechanism contributing pattern stylosa.