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Senula SF, Scavetta JT, Mueller UG, Seal JN, Kellner K. Cold adaptations along a range limit in an obligate symbiosis. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. F. Senula
- Department of Biology, The University of Texas at Tyler 3900 University Blvd. Tyler Texas
| | - J. T. Scavetta
- Department of Computer Science Rowan University Glassboro NJ USA
| | - U. G. Mueller
- Department of Integrative Biology University of Texas at Austin Austin TX USA
| | - J. N. Seal
- Department of Biology, The University of Texas at Tyler 3900 University Blvd. Tyler Texas
| | - K. Kellner
- Department of Biology, The University of Texas at Tyler 3900 University Blvd. Tyler Texas
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2
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Beigel K, Matthews AE, Kellner K, Pawlik CV, Greenwold M, Seal JN. Cophylogenetic analyses of Trachymyrmex ant-fungal specificity: "One to one with some exceptions". Mol Ecol 2021; 30:5605-5620. [PMID: 34424571 DOI: 10.1111/mec.16140] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 01/18/2023]
Abstract
Over the past few decades, large-scale phylogenetic analyses of fungus-gardening ants and their symbiotic fungi have depicted strong concordance among major clades of ants and their symbiotic fungi, yet within clades, fungus sharing is widespread among unrelated ant lineages. Sharing has been explained using a diffuse coevolution model within major clades. Understanding horizontal exchange within clades has been limited by conventional genetic markers that lack both interspecific and geographic variation. To examine whether reports of horizontal exchange were indeed due to symbiont sharing or the result of employing relatively uninformative molecular markers, samples of Trachymyrmex arizonensis and Trachymyrmex pomonae and their fungi were collected from native populations in Arizona and genotyped using conventional marker genes and genome-wide single nucleotide polymorphisms (SNPs). Conventional markers of the fungal symbionts generally exhibited cophylogenetic patterns that were consistent with some symbiont sharing, but most fungal clades had low support. SNP analysis, in contrast, indicated that each ant species exhibited fidelity to its own fungal subclade with only one instance of a colony growing a fungus that was otherwise associated with a different ant species. This evidence supports a pattern of codivergence between Trachymyrmex species and their fungi, and thus a diffuse coevolutionary model may not accurately predict symbiont exchange. These results suggest that fungal sharing across host species in these symbioses may be less extensive than previously thought.
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Affiliation(s)
- Katherine Beigel
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Alix E Matthews
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA.,College of Sciences and Mathematics and Molecular Biosciences Program, Arkansas State University, Jonesboro, Arkansas, USA
| | - Katrin Kellner
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Christine V Pawlik
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Matthew Greenwold
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
| | - Jon N Seal
- Department of Biology, The University of Texas at Tyler, Tyler, Texas, USA
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Oyserman BO, Cordovez V, Flores SS, Leite MFA, Nijveen H, Medema MH, Raaijmakers JM. Extracting the GEMs: Genotype, Environment, and Microbiome Interactions Shaping Host Phenotypes. Front Microbiol 2021; 11:574053. [PMID: 33584558 PMCID: PMC7874016 DOI: 10.3389/fmicb.2020.574053] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022] Open
Abstract
One of the fundamental tenets of biology is that the phenotype of an organism (Y) is determined by its genotype (G), the environment (E), and their interaction (GE). Quantitative phenotypes can then be modeled as Y = G + E + GE + e, where e is the biological variance. This simple and tractable model has long served as the basis for studies investigating the heritability of traits and decomposing the variability in fitness. The importance and contribution of microbe interactions to a given host phenotype is largely unclear, nor how this relates to the traditional GE model. Here we address this fundamental question and propose an expansion of the original model, referred to as GEM, which explicitly incorporates the contribution of the microbiome (M) to the host phenotype, while maintaining the simplicity and tractability of the original GE model. We show that by keeping host, environment, and microbiome as separate but interacting variables, the GEM model can capture the nuanced ecological interactions between these variables. Finally, we demonstrate with an in vitro experiment how the GEM model can be used to statistically disentangle the relative contributions of each component on specific host phenotypes.
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Affiliation(s)
- Ben O. Oyserman
- Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, Netherlands
- Bioinformatics Group, Wageningen University & Research, Wageningen, Netherlands
| | - Viviane Cordovez
- Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, Netherlands
- Institute of Biology, Leiden University, Leiden, Netherlands
| | | | - Marcio F. A. Leite
- Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, Netherlands
| | - Harm Nijveen
- Bioinformatics Group, Wageningen University & Research, Wageningen, Netherlands
| | - Marnix H. Medema
- Bioinformatics Group, Wageningen University & Research, Wageningen, Netherlands
| | - Jos M. Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology, Wageningen, Netherlands
- Institute of Biology, Leiden University, Leiden, Netherlands
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Amaral KD, Gandra LC, de Souza DJ, Della Lucia TMC. Deleterious action of azadirachtin against the mutualistic fungus of leaf-cutting ants. J Basic Microbiol 2020; 60:931-937. [PMID: 33135277 DOI: 10.1002/jobm.202000541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/24/2020] [Indexed: 11/11/2022]
Abstract
Leaf-cutting ants have a beneficial and obligatory relationship with the fungus that they grow. This mutualism allowed the evolutionary success of these ants. The great defoliation capacity of these insects, which often exceeds the level of tolerable economic damage, includes them as severe pests in many cultures. However, given the close relationship between these two agents of mutualism, it is expected that an impact on the fungus will reflect on the performance of the colony as a whole. Therefore, the effect of azadirachtin on the development, and the macronutrient composition of Leucoagaricus gongylophorus was evaluated. Azadirachtin reduced the final fungal mass at the end of treatment at all concentrations tested, but did not reduce the final growth area. A reduction in the amount of hyphae produced with increasing azadirachtin concentration was also observed. Regarding macronutrients, the compound did not affect their total amount in the fungus. Thus, it is observed that azadirachtin did not alter the composition of L. gongylophorus macronutrients, but inhibited its growth by reducing the number of hyphae produced. This reduction reflects directly on the amount of nutrients offered to the workers and the queen and may improve the management of these insects.
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Affiliation(s)
- Karina D Amaral
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Lailla C Gandra
- Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Viçosa, Florestal, Minas Gerais, Brazil
| | - Danival J de Souza
- Programa de Pós-graduação em Produção Vegetal, Universidade Federal do Tocantins, Gurupi, Tocantins, Brazil
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High diversity and multiple invasions to North America by fungi grown by the northern-most Trachymyrmex and Mycetomoellerius ant species. FUNGAL ECOL 2020. [DOI: 10.1016/j.funeco.2019.100878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Senula SF, Scavetta JT, Banta JA, Mueller UG, Seal JN, Kellner K. Potential Distribution of Six North American Higher-Attine Fungus-Farming Ant (Hymenoptera: Formicidae) Species. JOURNAL OF INSECT SCIENCE (ONLINE) 2019; 19:24. [PMID: 31854452 PMCID: PMC6921375 DOI: 10.1093/jisesa/iez118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Indexed: 06/10/2023]
Abstract
Ants are among the most successful insects in Earth's evolutionary history. However, there is a lack of knowledge regarding range-limiting factors that may influence their distribution. The goal of this study was to describe the environmental factors (climate and soil types) that likely impact the ranges of five out of the eight most abundant Trachymyrmex species and the most abundant Mycetomoellerius species in the United States. Important environmental factors may allow us to better understand each species' evolutionary history. We generated habitat suitability maps using MaxEnt for each species and identified associated most important environmental variables. We quantified niche overlap between species and evaluated possible congruence in species distribution. In all but one model, climate variables were more important than soil variables. The distribution of M. turrifex (Wheeler, W.M., 1903) was predicted by temperature, specifically annual mean temperature (BIO1), T. arizonensis (Wheeler, W.M., 1907), T. carinatus, and T. smithi Buren, 1944 were predicted by precipitation seasonality (BIO15), T. septentrionalis (McCook, 1881) were predicted by precipitation of coldest quarter (BIO19), and T. desertorum (Wheeler, W.M., 1911) was predicted by annual flood frequency. Out of 15 possible pair-wise comparisons between each species' distributions, only one was statistically indistinguishable (T. desertorum vs T. septentrionalis). All other species distribution comparisons show significant differences between species. These models support the hypothesis that climate is a limiting factor in each species distribution and that these species have adapted to temperatures and water availability differently.
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Affiliation(s)
- Sarah F Senula
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
| | - Joseph T Scavetta
- Department of Computer Science, Rowan University, Glassboro, NJ, USA
| | - Joshua A Banta
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
| | - Ulrich G Mueller
- Section of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Jon N Seal
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
| | - Katrin Kellner
- Department of Biology, University of Texas at Tyler, Tyler, TX, USA
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7
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Smith CC, Weber JN, Mikheyev AS, Roces F, Bollazzi M, Kellner K, Seal JN, Mueller UG. Landscape genomics of an obligate mutualism: Concordant and discordant population structures between the leafcutter ant Atta texana and its two main fungal symbiont types. Mol Ecol 2019; 28:2831-2845. [PMID: 31141257 DOI: 10.1111/mec.15111] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 12/22/2022]
Abstract
To explore landscape genomics at the range limit of an obligate mutualism, we use genotyping-by-sequencing (ddRADseq) to quantify population structure and the effect of host-symbiont interactions between the northernmost fungus-farming leafcutter ant Atta texana and its two main types of cultivated fungus. Genome-wide differentiation between ants associated with either of the two fungal types is of the same order of magnitude as differentiation associated with temperature and precipitation across the ant's entire range, suggesting that specific ant-fungus genome-genome combinations may have been favoured by selection. For the ant hosts, we found a broad cline of genetic structure across the range, and a reduction of genetic diversity along the axis of range expansion towards the range margin. This population-genetic structure was concordant between the ants and one cultivar type (M-fungi, concordant clines) but discordant for the other cultivar type (T-fungi). Discordance in population-genetic structures between ant hosts and a fungal symbiont is surprising because the ant farmers codisperse with their vertically transmitted fungal symbionts. Discordance implies that (a) the fungi disperse also through between-nest horizontal transfer or other unknown mechanisms, and (b) genetic drift and gene flow can differ in magnitude between each partner and between different ant-fungus combinations. Together, these findings imply that variation in the strength of drift and gene flow experienced by each mutualistic partner affects adaptation to environmental stress at the range margin, and genome-genome interactions between host and symbiont influence adaptive genetic differentiation of the host during range evolution in this obligate mutualism.
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Affiliation(s)
- Chad C Smith
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Jesse N Weber
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Department of Biological Sciences, University of Alaska, Anchorage, Alaska
| | | | - Flavio Roces
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Martin Bollazzi
- Section of Entomology, Universidad de la República, Montevideo, Uruguay
| | - Katrin Kellner
- Department of Biology, University of Texas at Tyler, Tyler, Texas
| | - Jon N Seal
- Department of Biology, University of Texas at Tyler, Tyler, Texas
| | - Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
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Mueller UG, Kardish MR, Ishak HD, Wright AM, Solomon SE, Bruschi SM, Carlson AL, Bacci M. Phylogenetic patterns of ant-fungus associations indicate that farming strategies, not only a superior fungal cultivar, explain the ecological success of leafcutter ants. Mol Ecol 2018; 27:2414-2434. [PMID: 29740906 DOI: 10.1111/mec.14588] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 01/18/2023]
Abstract
To elucidate fungicultural specializations contributing to ecological dominance of leafcutter ants, we estimate the phylogeny of fungi cultivated by fungus-growing (attine) ants, including fungal cultivars from (i) the entire leafcutter range from southern South America to southern North America, (ii) all higher-attine ant lineages (leafcutting genera Atta, Acromyrmex; nonleafcutting genera Trachymyrmex, Sericomyrmex) and (iii) all lower-attine lineages. Higher-attine fungi form two clades, Clade-A fungi (Leucocoprinus gongylophorus, formerly Attamyces) previously thought to be cultivated only by leafcutter ants, and a sister clade, Clade-B fungi, previously thought to be cultivated only by Trachymyrmex and Sericomyrmex ants. Contradicting this traditional view, we find that (i) leafcutter ants are not specialized to cultivate only Clade-A fungi because some leafcutter species ranging across South America cultivate Clade-B fungi; (ii) Trachymyrmex ants are not specialized to cultivate only Clade-B fungi because some Trachymyrmex species cultivate Clade-A fungi and other Trachymyrmex species cultivate fungi known so far only from lower-attine ants; (iii) in some locations, single higher-attine ant species or closely related cryptic species cultivate both Clade-A and Clade-B fungi; and (iv) ant-fungus co-evolution among higher-attine mutualisms is therefore less specialized than previously thought. Sympatric leafcutter ants can be ecologically dominant when cultivating either Clade-A or Clade-B fungi, sustaining with either cultivar-type huge nests that command large foraging territories; conversely, sympatric Trachymyrmex ants cultivating either Clade-A or Clade-B fungi can be locally abundant without achieving the ecological dominance of leafcutter ants. Ecological dominance of leafcutter ants therefore does not depend primarily on specialized fungiculture of L. gongylophorus (Clade-A), but must derive from ant-fungus synergisms and unique ant adaptations.
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Affiliation(s)
- Ulrich G Mueller
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Melissa R Kardish
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Center for Population Biology, University of California, Davis, California
| | - Heather D Ishak
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Department of Medicine, Stanford University, Stanford, California
| | - April M Wright
- Department of Biological Science, Southeastern Louisiana University, Hammond, Louisiana
| | - Scott E Solomon
- Department of Ecology and Evolutionary Biology, Rice University, Houston, Texas.,Department of Entomology, Smithsonian Institution, Washington, District of Columbia
| | - Sofia M Bruschi
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas.,Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Alexis L Carlson
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas
| | - Maurício Bacci
- Centro de Estudos de Insetos Sociais, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
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