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Dejean A, Azémar F, Naskrecki P, Tindo M, Rossi V, Faucher C, Gryta H. Mutualistic interactions between ants and fungi: A review. Ecol Evol 2023; 13:e10386. [PMID: 37529578 PMCID: PMC10375366 DOI: 10.1002/ece3.10386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023] Open
Abstract
The large amount of dead plant biomass caused by the final extinction events triggered a fungi proliferation that mostly differentiated into saprophytes degrading organic matter; others became parasites, predators, likely commensals, and mutualists. Among the last, many have relationships with ants, the most emblematic seen in the Neotropical myrmicine Attina that cultivate Basidiomycota for food. Among them, leaf-cutting, fungus-growing species illustrate an ecological innovation because they grow fungal gardens from fresh plant material rather than arthropod frass and plant debris. Myrmecophytes shelter "plant-ants" in hollow structures, the domatia, whose inner walls are lined with thin-walled Ascomycota hyphae that, in certain cases, are eaten by the ants, showing a form of convergence. Typically, these Ascomycota have antibacterial properties illustrating cases of farming for protection. Ant gardens, or mutualistic associations between certain ant species and epiphytes, shelter endophytic fungi that promote the growth of the epiphytes. Because the cell walls of certain Ascomycota hyphae remain sturdy after the death of the mycelium, they form resistant fibers used by ants to reinforce their constructions (e.g., galleries, shelters for tended hemipterans, and carton nests). Thus, we saw cases of "true" fungal agriculture involving planting, cultivating, and harvesting Basidiomycota for food with Attina. A convergence with "plant-ants" feeding on Ascomycota whose antibacterial activity is generally exploited (i.e., farming for protection). The growth of epiphytes was promoted by endophytic fungi in ant gardens. Finally, farming for structural materials occurred with, in one case, a leaf-cutting, fungus-growing ant using Ascomycota fibers to reinforce its nests.
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Affiliation(s)
- Alain Dejean
- Laboratoire Écologie Fonctionnelle et EnvironnementUniversité de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 – Paul Sabatier (UPS)ToulouseFrance
- UMR EcoFoG, AgroParisTechCirad, CNRS, INRA, Université des Antilles, Université de GuyaneKourouFrance
| | - Frédéric Azémar
- Laboratoire Écologie Fonctionnelle et EnvironnementUniversité de Toulouse, CNRS, Toulouse INP, Université Toulouse 3 – Paul Sabatier (UPS)ToulouseFrance
| | - Piotr Naskrecki
- Museum of Comparative ZoologyHarvard UniversityCambridgeMassachusettsUSA
| | - Maurice Tindo
- Laboratory of Biology and Physiology of Animal Organisms, Faculty of ScienceUniversity of DoualaDoualaCameroon
| | - Vivien Rossi
- Remote Sensing and Forest Ecology Lab, Higher Teacher's Training CollegeMarien Ngouabi UniversityBrazzavilleDemocratic Republic of the Congo
- R U Forests and Societies, CIRADBrazzavilleDemocratic Republic of the Congo
| | - Christian Faucher
- Laboratoire Evolution & Diversité Biologique (EDB UMR 5174) CNRSIRD, Université Toulouse 3ToulouseFrance
| | - Hervé Gryta
- Laboratoire Evolution & Diversité Biologique (EDB UMR 5174) CNRSIRD, Université Toulouse 3ToulouseFrance
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Abstract
Within social insect colonies, microbiomes often differ between castes due to their different functional roles and between colony locations. Trachymyrmex septentrionalis fungus-growing ants form colonies throughout the eastern United States and northern Mexico that include workers, female and male alates (unmated reproductive castes), larvae, and pupae. How T. septentrionalis microbiomes vary across this geographic range and between castes is unknown. Our sampling of individual ants from colonies across the eastern United States revealed a conserved T. septentrionalis worker ant microbiome and revealed that worker ant microbiomes are more conserved within colonies than between them. A deeper sampling of individual ants from two colonies that included all available castes (pupae, larvae, workers, and female and male alates), from both before and after adaptation to controlled laboratory conditions, revealed that ant microbiomes from each colony, caste, and rearing condition were typically conserved within but not between each sampling category. Tenericute bacterial symbionts were especially abundant in these ant microbiomes and varied widely in abundance between sampling categories. This study demonstrates how individual insect colonies primarily drive the composition of their microbiomes and shows that these microbiomes are further modified by developmental differences between insect castes and the different environmental conditions experienced by each colony. IMPORTANCE This study investigates microbiome assembly in the fungus-growing ant Trachymyrmex septentrionalis, showing how colony, caste, and lab adaptation influence the microbiome and revealing unique patterns of mollicute symbiont abundance. We find that ant microbiomes differ strongly between colonies but less so within colonies. Microbiomes of different castes and following lab adaptation also differ in a colony-specific manner. This study advances our understanding of the nature of individuality in social insect microbiomes and cautions against the common practice of only sampling a limited number of populations to understand microbiome diversity and function.
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Shik JZ, Kooij PW, Donoso DA, Santos JC, Gomez EB, Franco M, Crumière AJJ, Arnan X, Howe J, Wcislo WT, Boomsma JJ. Nutritional niches reveal fundamental domestication trade-offs in fungus-farming ants. Nat Ecol Evol 2020; 5:122-134. [PMID: 33106603 PMCID: PMC7610523 DOI: 10.1038/s41559-020-01314-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 08/25/2020] [Indexed: 02/06/2023]
Abstract
During crop domestication, human farmers traded greater productivity for higher crop vulnerability outside specialized cultivation conditions. We found a similar domestication tradeoff across the major co-evolutionary transitions in farming systems of attine ants. First, the fundamental nutritional niches (FNNs) of cultivars narrowed during ~ 60 million years of naturally selected domestication, and laboratory experiments showed that ant farmers representing subsequent domestication stages strictly regulate protein harvest relative to cultivar FNNs. Second, ants with different farming systems differed in their abilities to harvest the resources that best matched the nutritional needs of their fungal cultivars. This was assessed by quantifying realized nutritional niches (RNNs) from analyses of items collected from the mandibles of laden ant foragers in the field. Third, extensive field collections suggest that among-colony genetic diversity of cultivars in small-scale farms may offer population-wide resilience benefits that species with large-scale farming colonies achieve by more elaborate and demanding cultivation practices of less diverse crops. Our results underscore that naturally selected farming systems have potential to shed light on nutritional tradeoffs that shaped the course of culturally evolved human farming.
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Affiliation(s)
- Jonathan Z Shik
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark. .,Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark. .,Smithsonian Tropical Research Institute, Panama City, Republic of Panama.
| | - Pepijn W Kooij
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Comparative Fungal Biology, Department of Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, London, UK.,Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, Brazil
| | - David A Donoso
- Departamento de Biología, Escuela Politécnica Nacional, Quito, Ecuador.,Centro de Investigación de la Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Quito, Ecuador
| | - Juan C Santos
- Department of Biological Sciences, St. John's University, New York, NY, USA
| | - Ernesto B Gomez
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Mariana Franco
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Antonin J J Crumière
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Xavier Arnan
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Cerdanyola del Vallès, Spain.,Department of Biological Sciences, University of Pernambuco, Garanhuns, Brazil
| | - Jack Howe
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Department of Zoology, University of Oxford, Oxford, UK
| | - William T Wcislo
- Smithsonian Tropical Research Institute, Panama City, Republic of Panama
| | - Jacobus J Boomsma
- Section of Ecology and Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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