Data from: Reproductive character displacement shapes a spatially structured petal color polymorphism in Leavenworthia stylosa

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