XVI International Botanical Congess

Since Grant's classic 1949 paper, pollinator-mediated selection has been viewed as an important mechanism of adaptation and speciation in plants. Here we report the results of experiments designed to estimate the genetic and ecological contributions to pollinator preference in two closely related monkeyflowers, bee-pollinated Mimulus lewisii and hummingbird-pollinated M. cardinalis. Using linkage mapping techniques, we find that most floral traits have at least one Quantitative Trait Locus (QTL) of large effect (>25% PVE). Field experiments with F2s showed that bees prefer large flowers low in anthocyanin and carotenoid pigments, while hummingbirds favored nectar-rich flowers high in anthocyanins. Our results suggest that genes of large have contributed to floral evolution in these monkeyflowers.