Abstract
Animal pollinators mediate gene flow among plant populations, but, in
contrast to well-studied topographic and (Pleistocene) environmental
isolating barriers, their impact on population genetic differentiation
remains largely unexplored. Comparatively investigating how these
multifarious factors drive microevolutionary histories is, however,
crucial for better resolving macroevolutionary patterns of plant
diversification. We here combined genomic analyses with landscape
genetics and niche modelling across six related Neotropical plant
species (424 individuals across 33 localities) differing in pollination
strategy to test the hypothesis that highly mobile (vertebrate)
pollinators more effectively link isolated localities than less mobile
(bee) pollinators. We found consistently higher genetic differentiation
(FST ) among localities of bee- than
vertebrate-pollinated species with increasing geographic distance,
topographic barriers and historic climatic instability. High admixture
among montane populations further suggested relative climatic stability
of Neotropical montane forests during the Pleistocene. Overall, our
results indicate that pollinators may differentially impact the
potential for allopatric speciation, thereby critically influencing
diversification histories at macroevolutionary scales.
Keywords : pollinator shifts, population differentiation, genetic
diversity, Pleistocene climatic fluctuations, mountain biodiversity,
tropical rain forests, Andes, Melastomataceae