Impacts of Flowering Density on Pollen Dispersal and Gametic Diversity Are Scale Dependent

Pollen dispersal is a key evolutionary and ecological process, but the degree to which variation in the density of concurrently flowering conspecific plants (i.e., coflowering density) shapes pollination patterns remains understudied. We monitored coflowering density and corresponding pollination patterns of the insect-pollinated palm Oenocarpus bataua in northwestern Ecuador and found that the influence of coflowering density on these patterns was scale dependent: high neighborhood densities were associated with reductions in pollen dispersal distance and gametic diversity of progeny arrays, whereas we observed the opposite pattern at the landscape scale. In addition, neighborhood coflowering density also impacted forward pollen dispersal kernel parameters, suggesting that low neighborhood densities encourage pollen movement and may promote gene flow and genetic diversity. Our work reveals how coflowering density at different spatial scales influences pollen movement, which in turn informs our broader understanding of the mechanisms underlying patterns of genetic diversity and gene flow within populations of plants.

Automated summary

This study investigated the coflowering density and corresponding pollination patterns of the insect-pollinated palm Oenocarpus bataua in northwestern Ecuador. The results showed that the influence of coflowering density on pollination patterns was scale dependent, with high neighborhood densities leading to reductions in pollen dispersal distance and gametic diversity of progeny arrays at smaller scales, but the opposite pattern observed at the landscape scale. In addition, neighborhood coflowering density also impacted forward pollen dispersal kernel parameters, indicating that low neighborhood densities promote pollen movement, gene flow, and genetic diversity. This research reveals how coflowering density at different spatial scales affects pollen movement and enhances our understanding of mechanisms underlying genetic diversity and gene flow patterns within plant populations.