Modelling pollinator and nonpollinator selection on flower colour variation

Author(s)
Brigitte Tenhumberg, Agnes Dellinger, Stacey D. Smith
Abstract

Flower colour variation is ubiquitous within and between populations, which is why it has long been a focal point for studies of natural selection. This body of work has uncovered a wide range of selective agents, including pollinators, herbivores and various abiotic factors. Nevertheless, we lack an integrative framework for predicting the phenotypic outcome in terms of floral pigmentation when these forces act collectively and often in opposition. We here present such a framework through a model that incorporates selection on pigmentation at the vegetative phase (i.e. through survival to reproduction) and at the flowering phase (i.e. on pollinator attraction). We focus on anthocyanins as common class of pigments although the model is equally applicable to any compounds that can be jointly expressed in vegetative tissue and in flowers. We explore the dynamics of our model in a theoretical context and in four scenarios based on classic systems for studying selection on flower colour. Our model predicts that pollinators are the main driver for flower colour evolution, but selection on seedling survival plays a major role in the absence of pollen limitation, that is, if pollinator abundance is sufficiently high, or if pollinator preference is absent or weak (high variance in colour preference). In each of the case studies, our model recovered the predicted patterns of fitness for each floral morph given the strength and nature of selection. This work suggests that selection at the vegetative phase must act alone or be exceptionally strong to negate pollinator preference for particular colours. Nevertheless, the influence of differential survival associated with anthocyanin production leaves a clear signature on the fitness curves, suggesting that nonpollinator agents of selection can often be detected from empirical data. Synthesis: Overall, the application of this model to empirical systems will be key for understanding how flower colour diversity evolves and for predicting how changes in climate and pollinator communities may jointly alter evolutionary trajectories.

Organisation(s)
External organisation(s)
University of Nebraska-Lincoln, University of Colorado, Boulder
Journal
Journal of Ecology
Volume
111
Pages
746-760
No. of pages
15
ISSN
0022-0477
DOI
https://doi.org/10.1111/1365-2745.14057
Publication date
12-2022
Peer reviewed
Yes
Austrian Fields of Science 2012
106038 Reproductive biology
Keywords
ASJC Scopus subject areas
Ecology, Evolution, Behavior and Systematics, Plant Science, Ecology
Sustainable Development Goals
SDG 13 - Climate Action
Portal url
https://ucris.univie.ac.at/portal/en/publications/modelling-pollinator-and-nonpollinator-selection-on-flower-colour-variation(cc5b1cf7-ac0b-47ca-9de6-6ae3980611a3).html