Plant dispersion in the Neotropics, associating fruit traits and biotic interchanges to and inside the Neotropics: biogeography of Bocageeae (Annonaceae)

Abstract

The Neotropics are the most species-rich tropical region in the world and have been considered an engine of plant diversity to the planet, as species leaving the American tropics has largely exceeded immigration during the Cenozoic. Thus, biotic interchanges have played a key role in the Neotropical assembly. Despite that, some important components of the Neotropical flora have been hypothesised as of Paleotropical origin through geodispersal by the boreotropical connection. Most of the woody tropical plants disperse theirs seed by fruit-eating animal. However, long-distance dispersal is rare and depends on large-bodied and wide-ranging frugivorous megafauna or strong-flying volant frugivores. The first prefers large, green or brow fruits and/or syncarpous fruits, the mammal trait syndrome; the latter are attracted by small seeds, a smooth exocarp, dehiscent or moniliform fruits and/or cauliflorous fruits, the bird/bat trait syndrome. In tribe Bocageeae, a lineage belonging to the plant family Annonaceae, both fruit traits are present. Bocageeae comprises 66 species, distributed among eight genera. While most genera are exclusively Neotropical, Mkilua is monotypic and endemic to East Africa. The origin of Bocageeae is probably Paleotropical. Its assembly has involved biotic interchange both intercontinentally and inside the Neotropics, among different regions. This high ability to disperse may be explained by the diversity of fruits traits in the tribe. Thus, Bocageeae is a good study case to understand how biotic interchanges associated with the plant trait to disperse helped to shape the striking biodiversity in the Neotropics. We will test which fruit trait syndrome is associate to intercontinental dispersal and which one is associated to the dispersals inside the Neotropics. We will test whether these characters transformations in fruit traits are associated with shifts in diversification rates. For this we will: (1) estimate time divergence and reconstruct the phylogeny of Bocageeae using hundreds of nuclear loci selected by targeted enrichment both with the Annonaceae and the Angiosperm 353 bating kits followed by high throughput sequencing; (2) reconstruct ancestral state evolution for fruit traits associate to long-distance dispersal; (3) test whether shifts in diversification rates are associate with particular fruits traits; (4) reconstruct ancestral ranges of Bocageeae.