Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Sep;108(9):1716-1730.
doi: 10.1002/ajb2.1735. Epub 2021 Sep 29.

Judge it by its shape: a pollinator-blind approach reveals convergence in petal shape and infers pollination modes in the genus Erythrina

Gonzalo Bilbao  1 , Anne Bruneau  1 , Simon Joly  1   2
Affiliations
Free article

Judge it by its shape: a pollinator-blind approach reveals convergence in petal shape and infers pollination modes in the genus Erythrina

Gonzalo Bilbao et al. Am J Bot. 2021 Sep.
Free article

Abstract

Premise: Pollinators are thought to exert selective pressures on plants, mediating the evolution of convergent floral shape often recognized as pollination syndromes. However, little is known about the accuracy of using petal shape for inferring convergence in pollination mode without a priori pollination information. Here we studied the genus Erythrina L. as a test case to assess whether ornithophyllous pollination modes (hummingbirds, passerines, sunbirds, or mixed pollination) can be inferred based on the evolutionary analysis of petal shape.

Methods: We characterized the two-dimensional dissected shape of standard, keel, and wing petals from 106 Erythrina species using geometric morphometrics and reconstructed a phylogenetic tree of 83 Erythrina species based on plastid trnL-F and nuclear ribosomal ITS sequences. We then used two phylogenetic comparative methods based on Ornstein-Uhlenbeck models, SURFACE and l1OU, to infer distinct morphological groups using petal shape and identify instances of convergent evolution. The effectiveness of these methods was evaluated by comparing the groups inferred to known pollinators.

Results: We found significant petal shape differences between hummingbird- and passerine-pollinated Erythrina species. Our analyses also revealed that petal combinations generally provided better inferences of pollinator types than individual petals and that the method and optimization criterion can affect the results.

Conclusions: We show that model-based approaches using petal shape can detect convergent evolution of floral shape and relatively accurately infer pollination modes in Erythrina. The inference power of the keel petals argues for a deeper investigation of their role in the pollination biology of Erythrina and other bird-pollinated legumes.

Keywords: Leguminosae; Ornstein-Uhlenbeck (OU) models; flower evolution; geometric morphometrics; morphological convergence; ornithophily; petal shape.

PubMed Disclaimer

References

REFERENCES

    1. Abdullah, M. I., I. E. Barakat, D. E. Games, P. Ludgate, V. G. Mavraganis, V. U. Ratnayake, and A. H. Jackson. 1979. Studies of Erythrina alkaloids, part III. GC/MS investigations of alkaloids in the seeds of a further fourteen species. Annals of the Missouri Botanical Garden 66: 533-540.
    1. Abrahamczyk, S., M. Kessler, D. Hanley, D. N. Karger, M. P. J. Müller, A. C. Knauer, F. Keller, et al. 2017. Pollinator adaptation and the evolution of floral nectar sugar composition. Journal of Evolutionary Biology 30: 112-127.
    1. Adams, D. C., and E. Otárola-Castillo. 2013. geomorph: an R package for the collection and analysis of geometric morphometric shape data. Methods in Ecology and Evolution 4: 393-399.
    1. Aigner, P. A. 2001. Optimality modeling and fitness trade-offs: when should plants become pollinator specialists? Oikos 95: 177-184.
    1. Arroyo, K. 1981. Breeding systems and pollination biology in the Leguminosae. Advances in Legume Systematics. Part 2: 723-769.

Publication types

LinkOut - more resources