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.