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Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants
Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore mor...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083703/ https://www.ncbi.nlm.nih.gov/pubmed/32211161 http://dx.doi.org/10.1002/ece3.6101 |
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author | Miller, Chelsea N. Whitehead, Susan R. Kwit, Charles |
author_facet | Miller, Chelsea N. Whitehead, Susan R. Kwit, Charles |
author_sort | Miller, Chelsea N. |
collection | PubMed |
description | Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaiosome phytochemical profiles explain the differential attractiveness of five species in the genus Trillium to eastern North American forest ants. Species were ranked from least to most attractive based on empirically‐derived seed dispersal probabilities in our study system, and we compared diaspore traits to test our hypotheses that more attractive species will have larger diaspores, greater concentrations of elaiosome fatty acids, and distinct elaiosome phytochemistry compared to the less attractive species. Diaspore length, width, mass, and elaiosome length were significantly greater in the more attractive species. Using gas chromatography–mass spectrometry, we found significantly higher concentrations of oleic, linoleic, hexadecenoic, stearic, palmitoleic, and total fatty acids in elaiosomes of the more attractive species. Multivariate assessments revealed that elaiosome phytochemical profiles, identified through liquid chromatography–mass spectrometry, were more homogeneous for the more attractive species. Random forest classification models (RFCM) identified several elaiosome phytochemicals that differed significantly among species. Random forest regression models revealed that some of the compounds identified by RFCM, including methylhistidine (α‐amino acid) and d‐glucarate (carbohydrate), were positively related to seed dispersal probabilities, while others, including salicylate (salicylic acid) and citrulline (L‐α‐amino acid), were negatively related. These results supported our hypotheses that the more attractive species of Trillium—which are geographically widespread compared to their less attractive, endemic congeners—are characterized by larger diaspores, greater concentrations of fatty acids, and distinct elaiosome phytochemistry. Further advances in our understanding of seed dispersal effectiveness in myrmecochorous systems will benefit from a portrayal of dispersal unit chemical and physical traits, and their combined responses to selection pressures. |
format | Online Article Text |
id | pubmed-7083703 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-70837032020-03-24 Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants Miller, Chelsea N. Whitehead, Susan R. Kwit, Charles Ecol Evol Original Research Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaiosome phytochemical profiles explain the differential attractiveness of five species in the genus Trillium to eastern North American forest ants. Species were ranked from least to most attractive based on empirically‐derived seed dispersal probabilities in our study system, and we compared diaspore traits to test our hypotheses that more attractive species will have larger diaspores, greater concentrations of elaiosome fatty acids, and distinct elaiosome phytochemistry compared to the less attractive species. Diaspore length, width, mass, and elaiosome length were significantly greater in the more attractive species. Using gas chromatography–mass spectrometry, we found significantly higher concentrations of oleic, linoleic, hexadecenoic, stearic, palmitoleic, and total fatty acids in elaiosomes of the more attractive species. Multivariate assessments revealed that elaiosome phytochemical profiles, identified through liquid chromatography–mass spectrometry, were more homogeneous for the more attractive species. Random forest classification models (RFCM) identified several elaiosome phytochemicals that differed significantly among species. Random forest regression models revealed that some of the compounds identified by RFCM, including methylhistidine (α‐amino acid) and d‐glucarate (carbohydrate), were positively related to seed dispersal probabilities, while others, including salicylate (salicylic acid) and citrulline (L‐α‐amino acid), were negatively related. These results supported our hypotheses that the more attractive species of Trillium—which are geographically widespread compared to their less attractive, endemic congeners—are characterized by larger diaspores, greater concentrations of fatty acids, and distinct elaiosome phytochemistry. Further advances in our understanding of seed dispersal effectiveness in myrmecochorous systems will benefit from a portrayal of dispersal unit chemical and physical traits, and their combined responses to selection pressures. John Wiley and Sons Inc. 2020-02-27 /pmc/articles/PMC7083703/ /pubmed/32211161 http://dx.doi.org/10.1002/ece3.6101 Text en © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. 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 | Original Research Miller, Chelsea N. Whitehead, Susan R. Kwit, Charles Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title | Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title_full | Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title_fullStr | Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title_full_unstemmed | Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title_short | Effects of seed morphology and elaiosome chemical composition on attractiveness of five Trillium species to seed‐dispersing ants |
title_sort | effects of seed morphology and elaiosome chemical composition on attractiveness of five trillium species to seed‐dispersing ants |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7083703/ https://www.ncbi.nlm.nih.gov/pubmed/32211161 http://dx.doi.org/10.1002/ece3.6101 |
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