How scent and nectar influence floral antagonists and mutualists

  1. Danny Kessler
  2. Mario Kallenbach
  3. Celia Diezel
  4. Eva Rothe
  5. Mark Murdock
  6. Ian T Baldwin  Is a corresponding author
  1. Max-Planck Institute for Chemical Ecology, Germany
  2. University of Pittsburgh, United States

Abstract

Many plants attract and reward pollinators with floral scents and nectar, respectively, but these traits can also incur fitness costs as they also attract herbivores. This dilemma, common to most flowering plants, could be solved by not producing nectar and/or scent, thereby cheating pollinators. Both nectar and scent are highly variable in native populations of coyote tobacco, Nicotiana attenuata, with some producing no nectar at all, uncorrelated with the tobacco's main floral attractant, benzylacetone. By silencing benzylacetone biosynthesis and nectar production in all combinations by RNAi, we experimentally uncouple these floral rewards/attractrants and measure their costs/benefits in the plant's native habitat and experimental tents. Both scent and nectar increase outcrossing rates for three, separately-tested, pollinators and both traits increase oviposition by a hawkmoth herbivore, with nectar being more influential than scent. These results underscore that it makes little sense to study floral traits as if they only mediated pollination services.

Article and author information

Author details

  1. Danny Kessler

    Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Jena, Germany
    Competing interests
    No competing interests declared.
  2. Mario Kallenbach

    Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Jena, Germany
    Competing interests
    No competing interests declared.
  3. Celia Diezel

    Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Jena, Germany
    Competing interests
    No competing interests declared.
  4. Eva Rothe

    Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Jena, Germany
    Competing interests
    No competing interests declared.
  5. Mark Murdock

    University of Pittsburgh, Pennsylvania, United States
    Competing interests
    No competing interests declared.
  6. Ian T Baldwin

    Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Jena, Germany
    For correspondence
    baldwin@ice.mpg.de
    Competing interests
    Ian T Baldwin, Senior editor, eLife.

Reviewing Editor

  1. Marcel Dicke, Wageningen University, Netherlands

Version history

  1. Received: March 21, 2015
  2. Accepted: June 30, 2015
  3. Accepted Manuscript published: July 1, 2015 (version 1)
  4. Version of Record published: August 11, 2015 (version 2)

Copyright

© 2015, Kessler et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 4,995
    views
  • 972
    downloads
  • 56
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Danny Kessler
  2. Mario Kallenbach
  3. Celia Diezel
  4. Eva Rothe
  5. Mark Murdock
  6. Ian T Baldwin
(2015)
How scent and nectar influence floral antagonists and mutualists
eLife 4:e07641.
https://doi.org/10.7554/eLife.07641

Share this article

https://doi.org/10.7554/eLife.07641

Further reading

    1. Ecology
    2. Plant Biology
    Kelsey JRP Byers, Florian P Schiestl
    Insight

    Floral scents and nectar attract both pollinators and other animals that may reduce the plant's fitness, and therefore put flowering plants in a challenging situation.

    1. Ecology
    Anna L Erdei, Aneth B David ... Teun Dekker
    Research Article Updated

    Over two decades ago, an intercropping strategy was developed that received critical acclaim for synergizing food security with ecosystem resilience in smallholder farming. The push–pull strategy reportedly suppresses lepidopteran pests in maize through a combination of a repellent intercrop (push), commonly Desmodium spp., and an attractive, border crop (pull). Key in the system is the intercrop’s constitutive release of volatile terpenoids that repel herbivores. However, the earlier described volatile terpenoids were not detectable in the headspace of Desmodium, and only minimally upon herbivory. This was independent of soil type, microbiome composition, and whether collections were made in the laboratory or in the field. Furthermore, in oviposition choice tests in a wind tunnel, maize with or without an odor background of Desmodium was equally attractive for the invasive pest Spodoptera frugiperda. In search of an alternative mechanism, we found that neonate larvae strongly preferred Desmodium over maize. However, their development stagnated and no larva survived. In addition, older larvae were frequently seen impaled and immobilized by the dense network of silica-fortified, non-glandular trichomes. Thus, our data suggest that Desmodium may act through intercepting and decimating dispersing larval offspring rather than adult deterrence. As a hallmark of sustainable pest control, maize–Desmodium push–pull intercropping has inspired countless efforts to emulate stimulo-deterrent diversion in other cropping systems. However, detailed knowledge of the actual mechanisms is required to rationally improve the strategy, and translate the concept to other cropping systems.