Assessing the links between pollinators and the genetic and epigenetic features of plant species with contrasting distribution ranges

In flowering plants, pollinators contribute to gene flow while they also respond to variation in plant traits together determined by genetic, epigenetic and environmental sources of variation. Consequently, a correlation between abundance and diversity of pollinators and the genetic and epigenetic characteristics of plant populations such as diversity or distinctiveness is expected. However, no study has explored these long-term dimensions of plant–pollinator interactions. Mediterranean narrow endemics often exhibit unexpectedly high levels of population genetic and epigenetic diversity. We hypothesize that pollinators may contribute to explain this pattern. Specifically, given the higher sensitivity of small, isolated population to gene flow, we expect a stronger association of pollinators with population genetic and epigenetic variability in narrow endemics than in widely distributed congeners. We studied five pairs of congeneric plant species, consisting of one narrow endemic with a restricted distribution and one widespread congener, found in the Sierra de Cazorla mountains (SE Spain). We characterized the pollinators in up to three populations per species to estimate their diversity and visitation rates. Additionally, we calculated the genetic and epigenetic diversity and distinctiveness of each population using AFLP markers and methylation-sensitive AFLP markers (MSAP), respectively. We assessed the relationship between pollinator diversity and visitation rates. The diversity of pollinators did not vary according to the plant´s distribution range, but visitation rate was higher in widespread species. As predicted, only narrow endemics showed a significant association between pollinators and their population genetic and epigenetic characteristics. Specifically, higher pollinator diversity and visitation rates entailed higher population genetic diversity and lower epigenetic distinctiveness. This work shows the importance of investigating the relationship between pollinator diversity and population genetics and epigenetics to better understand the evolution of plant rarity.