<b>Hybrid </b><b><i>Mimulus</i></b><b> flowers attract a new pollinator</b>

· Hybridization is common in flowering plants and is believed to be an important force driving adaptation and speciation. The flowers of hybrids often have new trait combinations, which, theoretically, could attract new pollinators.· In this study, we found that the hybrids between a hummingbird-pollinated species <i>Mimulus cardinalis</i> and a self-pollinated species <i>Mimulus parishii </i>attract bumblebees (<i>Bombus impatiens</i>), a pollinator not attracted to either of the progenitor species.· This novel attraction is explained by novel combinations of floral traits in hybrids, including most importantly petal color, in addition to nectar concentration and corolla size. To understand how petal color variation is perceived by bumblebees, we modelled the flower appearance under bee vision and showed that the color variation could impact the easiness of detection. We also found that <i>YUP</i>, the genetic locus explaining a large portion of color variation and previously shown to be important in bee attraction in other <i>Mimulus</i> species, also played an important role in this novel attraction.· These results together suggest that hybrid plants’ attraction to new pollinators could be an underexplored avenue for pollinator shift and speciation.