Mating Patterns and Pollinator Communities of the Invasive ShrubLonicera maackii: A Comparison between Interior Plants and Edge Plants

Abstract

Premise of research. It is known that outcrossing rates and mating structure are important factors determining the genetic structure of populations. Moreover, the composition and abundance of pollinator communities visiting flowers determine the distances over which the pollen is likely to be dispersed, which in turn affects the genetic structure of plant populations. For invasive plants, high outcrossing rates produce genetically diverse propagules for the colonization of uninvaded areas and facilitate the establishment of novel gene combinations that may affect their invasive ability. Here, we examine how differences in pollinator communities visiting flowers of the invasive shrub Lonicera maackii (Caprifoliaceae), growing along the edge and in the interior of a woodlot, affect their outcrossing rates and mating structure. Methodology. Five microsatellite marker loci were used to determine the outcrossing rates, levels of biparental inbreeding, and effective number of pollen donors siring the seed crop of plants growing along the edge and in the interior of an invaded woodlot. Pivotal results. We found that L. maackii is a predominantly outcrossing plant. Despite dissimilarities in composition and abundance of pollinator communities, there were no differences in outcrossing rates and biparental inbreeding between plants along the edge of the woodlot and those in the interior. However, the seed crop of plants in the interior was sired by more pollen donors than that of plants along the edge. Our findings suggest that plants differ in their ability to sire seeds, as maternal allele frequencies are different from those that sired their seeds. Conclusions. Lonicera maackii plants showed high outcrossing rates regardless of their position in the woodlot. Differences in the number of donors siring the seed crop between plants in the interior of the woodlot and those along the edge are most likely due to disparities in the abundance and composition of the pollinator communities.