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Published August 22, 2018 | Supplemental Material + Published
Journal Article Open

Unveiling community patterns and trophic niches of tropical and temperate ants using an integrative framework of field data, stable isotopes and fatty acids

Abstract

Background: The use and partitioning of trophic resources is a central aspect of community function. On the ground of tropical forests, dozens of ant species may be found together and ecological mechanisms should act to allow such coexistence. One hypothesis states that niche specialization is higher in the tropics, compared to temperate regions. However, trophic niches of most species are virtually unknown. Several techniques might be combined to study trophic niche, such as field observations, fatty acid analysis (FAA) and stable isotope analysis (SIA). In this work, we combine these three techniques to unveil partitioning of trophic resources in a tropical and a temperate community. We describe patterns of resource use, compare them between communities, and test correlation and complementarity of methods to unveil both community patterns and species' niches. Methods: Resource use was assessed with seven kinds of bait representing natural resources available to ants. Neutral lipid fatty acid (NLFA) profiles, and δ15N and δ13C isotope signatures of the species were also obtained. Community patterns and comparisons were analyzed with clustering, correlations, multivariate analyses and interaction networks. Results: Resource use structure was similar in both communities. Niche breadths (H′) and network metrics (Q and H_2′) indicated similar levels of generalization between communities. A few species presented more specialized niches, such as Wasmannia auropunctata and Lasius fuliginosus. Stable isotope signatures and NLFA profiles also indicated high generalization, although the latter differed between communities, with temperate species having higher amounts of fat and proportions of C18:1n9. Bait use and NLFA profile similarities were correlated, as well as species' specialization indices (d′) for the two methods. Similarities in δ^(15)N and bait use, and in δ^(13)C and NLFA profiles, were also correlated. Discussion: Our results agree with the recent view that specialization levels do not change with latitude or species richness. Partition of trophic resources alone does not explain species coexistence in these communities, and might act together with behavioral and environmental mechanisms. Temperate species presented NLFA patterns distinct from tropical ones, which may be related to environmental factors. All methods corresponded in their characterization of species' niches to some extent, and were robust enough to detect differences even in highly generalized communities. However, their combination provides a more comprehensive picture of resource use, and it is particularly important to understand individual niches of species. FAA was applied here for the first time in ant ecology, and proved to be a valuable tool due to its combination of specificity and temporal representativeness. We propose that a framework combining field observations with chemical analysis is valuable to understand resource use in ant communities.

Additional Information

© 2018 Rosumek et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited. Submitted 11 June 2018; Accepted 27 July 2018; Published 22 August 2018. The authors declare that they have no competing interests. Author Contributions: Felix B. Rosumek conceived and designed the experiments, performed the experiments, analyzed the data, contributed reagents/materials/analysis tools, prepared figures and/or tables, authored or reviewed drafts of the paper, approved the final draft. Nico Blüthgen conceived and designed the experiments, contributed reagents/materials/analysis tools, authored or reviewed drafts of the paper, approved the final draft. Adrian Brückner conceived and designed the experiments, analyzed the data, authored or reviewed drafts of the paper, approved the final draft. Florian Menzel conceived and designed the experiments, authored or reviewed drafts of the paper, contributed reagents/materials/analysis tools, approved the final draft. Gerhard Gebauer performed the experiments, contributed reagents/materials/analysis tools, approved the final draft. Michael Heethoff conceived and designed the experiments, contributed reagents/materials/analysis tools, authored or reviewed drafts of the paper, approved the final draft. Field Study Permissions: The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers): Fieldwork in Brazil was carried out under sampling permit SISBIO 51173-1 (ICMBio), and export permits 15BR019038/DF and 17BR025207/DF (IBAMA). No permits were needed in Germany. Data Availability: The following information was supplied regarding data availability: All raw data used for the analysis of this article are provided in Tables 2–4, and Table S1. Felix B. Rosumek and Adrian Brückner were supported by PhD scholarships from the Brazilian National Council of Technological and Scientific Development (CNPq), and the German National Academic Foundation (Studienstiftung des deutschen Volkes), respectively. This study was funded by CNPq (290075/2014-9), the German Research Foundation (DFG; HE 4593/5-1) and the Open Access Publishing Fund of DFG/Technische Universität Darmstadt. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. We thank Cristian Klunk, Frederico Rottgers Marcineiro, Larissa Zanette da Silva, Lukas Kauling and Felix Schilcher for assistance in fieldwork and sample sorting; Anna Ruppenthal for assistance in fieldwork and FAA of German ants; Christine Tiroch for technical assistance in EA-IRMS; and Rodrigo Machado Feitosa, Alexandre Casadei Ferreira, Thiago Sanches Ranzani da Silva and Francisco Hita Garcia for taxonomic assistance. We also thank the two anonymous reviewers for their valuable comments and suggestions.

Attached Files

Published - peerj-5467.pdf

Supplemental Material - Figure_S1.pdf

Supplemental Material - Supplemental_document_S1.pdf

Supplemental Material - Table_S1.pdf

Supplemental Material - Table_S2.pdf

Supplemental Material - Table_S3.pdf

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Created:
August 19, 2023
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October 23, 2023