Study group
Merianieae (Melastomataceae) are a Neotropical plant tribe of ca. 300
species, which has radiated recently in the tropical Andes (Dellinger et
al. 2021). Bee pollination is ancestral and common both among lowland
rainforest and cloud forest Merianieae, while shifts to vertebrate
pollination (3 x passerine, 3 x mixed assemblages of vertebrates) are
restricted to cloud forest species (for detailed empirical pollinator
obsevations, see Dellinger et al. 2014, 2019b, 2021). For this study, we
chose six species: lowland rainforest bee-pollinated Adelobotrys
adscendens (Sw.) Triana, cloud forest bee-pollinated Meriania
maxima Markgr., passerine-pollinated Axinaea costaricensisCogn., and three species pollinated by different combinations of
vertebrates (M. phlomoides (Triana) Almeda and M.
tomentosa (Cogn.) Wurdack, pollinated by hummingbirds and bats;M. sanguinea Wurdack, pollinated by hummingbirds, bats and
rodents, Dellinger et al. 2019b). Our sampling covers three independent
pollinator shifts from bee to vertebrate pollination (1: M.
sanguinea , 2: M. tomentosa and M. phlomoides (part of the
same subclade of Merianieae), 3. A. costaricensis ; Dellinger et
al. 2019b). The six species differ in distribution ranges and ecosystems
colonized (i.e. lowland rainforests, cloud forests, Fig. 1). Our
approach of directly addressing these differences through landscape
genetics and (historic) niche modelling allows us to objectively
evaluate the multifarious factors potentially structuring population
genetic diversity across multiple related species. Since all six species
have similarly small, dry, wind-dispersed seeds, gene flow attributable
to seed dispersal is comparable (and potentially limited to short
distances given the dense structure of tropical forests,
Kartzinel et al. 2013, Nazareno et
al. 2020).