Patch size changes the composition of flower visitors and influences pollen flow. (2nd November 2021) - C. B. S. Santos, Karen
ABSTRACT: Background: The spatial structure and size of plant populations affect foraging choices of pollinators and, consequently, pollen transfer within and between populations. Aims: To understand pollination patterns in relation to population size and pollinator selectivity we quantified patch size and pollen flow in natural populations of Richardia grandiflora, a neotropical perennial herb. Methods: We assessed the composition of flower visitors, the number of flowers visited, and the frequency of visits in patches of different sizes. In addition, we measured the inter- and intra-patch-size pollen transfer (pollen from patches of different sizes and from the same patch/same patch size, respectively) using fluorescent dyes as pollen analogues. Results: We recorded 22 species of insects, mainly bees, with Apis mellifera standing out as the major visitor in medium and large size patches. Large patches received a greater richness and abundance of flower visitors, had more flowers visited, and greater pollen flow overall (62%), representing 62% of the total intra-patch-size and 64% of inter-patch-size pollen flow. Alternatively, small patches represented 16% of the total intra-patch-size and 5% of the inter-patch-size pollen flow. Native bee species were found almost exclusively in small patches. Conclusion: Small patches are important for sustaining rare floral visitors while large patches are more relevant for diverse pollination events.