Low bee visitation rates explain pollinator shifts to vertebrates in tropical mountains

Author(s)
Agnes S. Dellinger, Rocio Pérez-Barrales, Fabián A. Michelangeli, Darin S. Penneys, Diana M. Fernández-Fernández, Jürg Schönenberger
Abstract

Evolutionary shifts from bee to vertebrate pollination are common in tropical mountains. Reduction in bee pollination efficiency under adverse montane weather conditions was proposed to drive these shifts. Although pollinator shifts are central to the evolution and diversification of angiosperms, we lack experimental evidence of the ecological processes underlying such shifts.
Here, we combine phylogenetic and distributional data for 138 species of the Neotropical plant tribe Merianieae (Melastomataceae) with pollinator observations of 11 and field pollination experiments of six species to test whether the mountain environment may indeed drive such shifts.
We demonstrate that shifts from bee to vertebrate pollination coincided with occurrence at high elevations. We show that vertebrates were highly efficient pollinators even under the harsh environmental conditions of tropical mountains, whereas bee pollination efficiency was lowered significantly through reductions in flower visitation rates. Furthermore, we show that pollinator shifts in Merianieae coincided with the final phases of the Andean uplift and were contingent on adaptive floral trait changes to alternative rewards and mechanisms facilitating pollen dispersal.
Our results provide evidence that abiotic environmental conditions (i.e. mountain climate) may indeed reduce the efficiency of a plant clade’s ancestral pollinator group and correlate with shifts to more efficient new pollinators.

Organisation(s)
Department of Botany and Biodiversity Research
External organisation(s)
University of Portsmouth, New York Bot Garden, University of North Carolina at Wilmington, Instituto Nacional de Biodiversidad, Quito
Journal
New Phytologist
Volume
231
Pages
864-877
No. of pages
36
ISSN
0028-646X
DOI
https://doi.org/10.1111/nph.17390
Publication date
04-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
106008 Botany, 106042 Systematic botany, 106012 Evolutionary research
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/low-bee-visitation-rates-explain-pollinator-shifts-to-vertebrates-in-tropical-mountains(6dae4551-e669-4af8-acdd-ffc79db5d1ea).html