Abstract Detail

Macroevolution

Lagomarsino, Laura [1], Forrestel, Elisabeth [2], Davis, Charles C. [3].

The repeated evolution of vertebrate pollination syndromes in the centropogonid clade (Campanulaceae: Lobelioideae), a recently diverged Andean plant clade.

Specialized biotic interactions, including those involving plants and their mutualistic pollinators, are often invoked to explain high species diversity. Pollination syndromes are inferred from suites of floral traits that are thought to be adaptive for the attraction and utilization of particular groups of pollinators. They are particularly useful for investigating biotic interactions at macroevolutionary scales, especially in large tropical groups where few large-scale pollination studies have been conducted. Here, we document the dynamic evolution of hummingbird and bat pollination syndromes in the centropogonids (Campanulaceae: Lobelioideae), an Andean-centered clade of ~550 angiosperm species whose rapid diversification was recently attributed to their association with vertebrate pollinators. Using phylogenetic principal components analysis, we demonstrate that flowers hypothesized to be adapted to pollination by hummingbirds and by bats, respectively, fall into separate regions of morphospace. This supports our use of pollination syndromes, which are further corroborated by ecological studies in this clade. We then document the repeated evolution of pollination syndromes: the centropogonids are ancestrally hummingbird pollinated, and bat pollination has evolved, on average, 14 times independently, with an average of nine reversions to hummingbird pollination. We further demonstrate a broad pattern of correlated evolution of key floral traits within these pollination syndromes. Finally, we detect no apparent difference in diversification rates between bird- and bat-pollinated lineages. These results collectively suggest that floral morphological diversity associated with pollination syndromes is very evolutionarily labile, likely as a result of selective pressures imposed by different pollinators. Moreover, they suggest that specialized pollination syndromes, such as hummingbird and bat pollination, are not evolutionary dead-ends. Instead, I hypothesize that shifts between vertebrate pollinators have greatly facilitated the maintenance of an ancestrally high diversification rate among centropogonid species via speciation by floral isolation.

1 - University of Missouri- St. Louis, Department of Biology, St. Louis, MO, USA
2 - The Arnold Arboretum of Harvard University, Boston, MA, 02130, USA
3 - Harvard University Herbaria, 22 Divinity Ave, Cambridge, MA, 02138

Keywords:
floral evolution
pollination syndrome
vertebrate pollination
phylogenetic comparative methods
diversification.

Presentation Type: Oral Paper
Session: 10, Macroevolution
Location: 202/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 3:00 PM
Number: 10007
Abstract ID:414
Candidate for Awards:None