RESUMO
BACKGROUND AND AIM: Plant disjunctions have fascinated biogeographers and ecologists for a long time. We use tribe Bocageeae (Annonaceae), a predominantly Neotropical plant group distributed across several present-day Neotropical biomes and with an African-American disjunction, to investigate long-distance dispersal mediated by frugivorous animals at both intercontinental and intracontinental scales. METHODS: We reconstructed a species-level phylogeny of tribe Bocageeae with a dataset composed of 116 nuclear markers. We sampled 70% of Bocageeae species, covering its geographic range and representing all eight genera. We estimated divergence times using BEAST, inferred ancestral range distributions and reconstructed ancestral states for fruit traits related to long-distance dispersal in a Bayesian framework. KEY RESULTS: The ancestral Bocageeae date to the Early Eocene and were inferred to occur in Africa and proto-Amazonia. Its ancestral fruits were large and dehiscent. The first lineage split gave rise to an exclusively Neotropical clade during the Middle Eocene, in proto-Amazonia. Range exchange between the Amazon and the Atlantic Forest occurred at least once during the Miocene, and from Amazonia to Central America and Mexico, during the Early Miocene. Transitions in different sets of fruit morphologies were inferred to be related to dispersal events across South American regions/biomes. CONCLUSIONS: In Bocageeae mammals may have been responsible for long-distance dispersal through the Boreotropics. In the Neotropics, proto-Amazonia is proposed to be the source for dispersal to other tropical American biomes. Long-distance dispersal may have happened via a wide range of dispersal guilds, depending on frugivore radiations, diversity, and abundance at particular time periods and places. Hence, inter- and intracontinental dispersal may not rely on a single dispersal syndrome or guild, but more on the availability of frugivorous lineages for seed dispersal.
RESUMO
Understanding how ecological interactions have shaped the evolutionary dynamics of species traits remains a challenge in evolutionary ecology. Combining trait evolution models and phylogenies, we analysed the evolution of characters associated with seed dispersal (fruit size and colour) and herbivory (spines) in Neotropical palms to infer the role of these opposing animal-plant interactions in driving evolutionary patterns. We found that the evolution of fruit colour and fruit size was associated in Neotropical palms, supporting the adaptive interpretation of seed-dispersal syndromes and highlighting the role of frugivores in shaping plant evolution. Furthermore, we revealed a positive association between fruit size and the presence of spines on palm leaves, bracteas and stems. We hypothesize that interactions between palms and large-bodied frugivores/herbivores may explain the evolutionary relationship between fruit size and spines. Large-bodied frugivores, such as extinct megafauna, besides consuming the fruits and dispersing large seeds, may also have consumed the leaves or damaged the plants, thus simultaneously favouring the evolution of large fruits and defensive structures. Our findings show how current trait patterns can be understood as the result of the interplay between antagonistic and mutualistic interactions that have happened throughout the evolutionary history of a clade.