Modelling pollinator and nonpollinator selection on flower colour variation

Brigitte Tenhumberg (Corresponding author), Agnes Dellinger, Stacey D. Smith

Publications: Contribution to journalArticlePeer Reviewed

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.

Original languageEnglish
Pages (from-to)746-760
Number of pages15
JournalJournal of Ecology
Volume111
Issue number4
Early online date8 Dec 2022
DOIs
Publication statusPublished - Apr 2023
Externally publishedYes

Austrian Fields of Science 2012

  • 106038 Reproductive biology

Keywords

  • anthocyanins
  • fitness
  • flavonoids
  • plant life history
  • pleiotropy
  • selection across life stages

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