Pollinator-mediated selection
Pollinator-mediated selection is an
Having a floral display that either attracts a variety of pollinators or is efficient in the exchanges that occur during pollination can have advantages for the reproductive success of plants. Thus, pollinator behavior is important to understand in relation to the evolution of flowering plants and in some cases pollinator behavior is thought to lead to specialized pollination syndromes where floral traits have co-evolved with their pollinators in a way that are a direct response to the selection occurring from their pollen vectors.[3] However, many flowering plants don’t display morphology that excludes all pollinators except the one they co-evolved with. The most effective pollinator principle posits that floral traits reflect the adaptation to the pollinator that is efficient at transferring the most pollen. Selection might actually favor some degree of generalization while some flowers can also retain particular traits that allow them to adapt to a certain type of pollinator, but will ultimately be molded by the pollinators that are the most effective and visit the most frequently.[4] This leads to shifts in pollination syndromes and to some genera having a high diversity of pollination syndromes among species, suggesting that pollinators are a primary selective force driving diversity and speciation.[5][6]
Pollinator-mediated selection requires isolation and therefore cannot function in sympatry. Floral isolation is a consequence of pollinator behavior that reduces inter-lineage pollen transfer, which reduces gene flow and increases the possibility for a transition to different syndromes.[5] Isolation with no gene flow between populations allows for the development of distinct species, thus speciation is a result of reproductive isolation and can be driven by pollinator-mediated selection.[1]