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Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?

1. Ant guards protect plants from herbivores, but can also hinder pollination by damaging reproductive structures and/or repelling pollinators. Natural selection should favour the evolution of plant traits that deter ants from visiting flowers during anthesis, without waiving their defensive service...

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Autores principales: Villamil, Nora, Boege, Karina, Stone, Graham N.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6559321/
https://www.ncbi.nlm.nih.gov/pubmed/31217634
http://dx.doi.org/10.1111/1365-2745.13135
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author Villamil, Nora
Boege, Karina
Stone, Graham N.
author_facet Villamil, Nora
Boege, Karina
Stone, Graham N.
author_sort Villamil, Nora
collection PubMed
description 1. Ant guards protect plants from herbivores, but can also hinder pollination by damaging reproductive structures and/or repelling pollinators. Natural selection should favour the evolution of plant traits that deter ants from visiting flowers during anthesis, without waiving their defensive services. The Distraction Hypothesis posits that rewarding ants with extrafloral nectar could reduce their visitation of flowers, reducing ant‐pollinator conflict while retaining protection of other structures. 2. We characterised the proportion of flowers occupied by ants and the number of ants per flower in a Mexican ant‐plant, Turnera velutina. We clogged extrafloral nectaries on field plants and observed the effects on patrolling ants, pollinators and ants inside flowers, and quantified the effects on plant fitness. Based on the Distraction Hypothesis, we predicted that preventing extrafloral nectar secretion should result in fewer ants active at extrafloral nectaries, more ants inside flowers and a higher proportion of flowers occupied by ants, leading to ant‐pollinator conflict, with reduced pollinator visitation and reduced plant fitness. 3. Overall ant activity inside flowers was low. Preventing extrafloral nectar secretion through clogging reduced the number of ants patrolling extrafloral nectaries, significantly increased the proportion of flowers occupied by ants from 6.1% to 9.7%, and reduced plant reproductive output through a 12% increase in the probability of fruit abortion. No change in the numbers of ants or pollinators inside flowers was observed. This is the first support for the Distraction Hypothesis obtained under field conditions, showing ecological and plant fitness benefits of the distracting function of extrafloral nectar during anthesis. 4. Synthesis. Our study provides the first field experimental support for the Distraction Hypothesis, suggesting that extrafloral nectaries located close to flowers may bribe ants away from reproductive structures during the crucial pollination period, reducing the probability of ant occupation of flowers, reducing ant‐pollinator conflict and increasing plant reproductive success.
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spelling pubmed-65593212019-06-17 Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict? Villamil, Nora Boege, Karina Stone, Graham N. J Ecol Multi‐trophic Interactions 1. Ant guards protect plants from herbivores, but can also hinder pollination by damaging reproductive structures and/or repelling pollinators. Natural selection should favour the evolution of plant traits that deter ants from visiting flowers during anthesis, without waiving their defensive services. The Distraction Hypothesis posits that rewarding ants with extrafloral nectar could reduce their visitation of flowers, reducing ant‐pollinator conflict while retaining protection of other structures. 2. We characterised the proportion of flowers occupied by ants and the number of ants per flower in a Mexican ant‐plant, Turnera velutina. We clogged extrafloral nectaries on field plants and observed the effects on patrolling ants, pollinators and ants inside flowers, and quantified the effects on plant fitness. Based on the Distraction Hypothesis, we predicted that preventing extrafloral nectar secretion should result in fewer ants active at extrafloral nectaries, more ants inside flowers and a higher proportion of flowers occupied by ants, leading to ant‐pollinator conflict, with reduced pollinator visitation and reduced plant fitness. 3. Overall ant activity inside flowers was low. Preventing extrafloral nectar secretion through clogging reduced the number of ants patrolling extrafloral nectaries, significantly increased the proportion of flowers occupied by ants from 6.1% to 9.7%, and reduced plant reproductive output through a 12% increase in the probability of fruit abortion. No change in the numbers of ants or pollinators inside flowers was observed. This is the first support for the Distraction Hypothesis obtained under field conditions, showing ecological and plant fitness benefits of the distracting function of extrafloral nectar during anthesis. 4. Synthesis. Our study provides the first field experimental support for the Distraction Hypothesis, suggesting that extrafloral nectaries located close to flowers may bribe ants away from reproductive structures during the crucial pollination period, reducing the probability of ant occupation of flowers, reducing ant‐pollinator conflict and increasing plant reproductive success. John Wiley and Sons Inc. 2019-03-06 2019-05 /pmc/articles/PMC6559321/ /pubmed/31217634 http://dx.doi.org/10.1111/1365-2745.13135 Text en © 2019 The Authors. Journal of Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Multi‐trophic Interactions
Villamil, Nora
Boege, Karina
Stone, Graham N.
Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title_full Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title_fullStr Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title_full_unstemmed Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title_short Testing the Distraction Hypothesis: Do extrafloral nectaries reduce ant‐pollinator conflict?
title_sort testing the distraction hypothesis: do extrafloral nectaries reduce ant‐pollinator conflict?
topic Multi‐trophic Interactions
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6559321/
https://www.ncbi.nlm.nih.gov/pubmed/31217634
http://dx.doi.org/10.1111/1365-2745.13135
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