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Holt JR, Cavichiolli de Oliveira N, Medina RF, Malacrinò A, Lindsey ARI. Insect-microbe interactions and their influence on organisms and ecosystems. Ecol Evol 2024; 14:e11699. [PMID: 39041011 PMCID: PMC11260886 DOI: 10.1002/ece3.11699] [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: 01/30/2024] [Revised: 06/14/2024] [Accepted: 06/21/2024] [Indexed: 07/24/2024] Open
Abstract
Microorganisms are important associates of insect and arthropod species. Insect-associated microbes, including bacteria, fungi, and viruses, can drastically impact host physiology, ecology, and fitness, while many microbes still have no known role. Over the past decade, we have increased our knowledge of the taxonomic composition and functional roles of insect-associated microbiomes and viromes. There has been a more recent shift toward examining the complexity of microbial communities, including how they vary in response to different factors (e.g., host genome, microbial strain, environment, and time), and the consequences of this variation for the host and the wider ecological community. We provide an overview of insect-microbe interactions, the variety of associated microbial functions, and the evolutionary ecology of these relationships. We explore the influence of the environment and the interactive effects of insects and their microbiomes across trophic levels. Additionally, we discuss the potential for subsequent synergistic and reciprocal impacts on the associated microbiomes, ecological interactions, and communities. Lastly, we discuss some potential avenues for the future of insect-microbe interactions that include the modification of existing microbial symbionts as well as the construction of synthetic microbial communities.
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Affiliation(s)
| | | | - Raul F. Medina
- Department of EntomologyTexas A&M University, Minnie Bell Heep CenterCollege StationTexasUSA
| | - Antonino Malacrinò
- Department of AgricultureUniversità Degli Studi Mediterranea di Reggio CalabriaReggio CalabriaItaly
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2
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Fortier CE, Musso AE, Evenden ML, Zaharia LI, Cooke JEK. Evidence that Ophiostomatoid Fungal Symbionts of Mountain Pine Beetle Do Not Play a Role in Overcoming Lodgepole Pine Defenses During Mass Attack. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:445-458. [PMID: 38240660 DOI: 10.1094/mpmi-06-23-0077-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) is a devastating forest insect pest that has killed millions of hectares of pines in western North America over the past two decades. Like other bark beetles, MPB vectors ophiostomatoid fungal species, some of which are pathogenic to host pine species. The phytopathogenicity of these fungal symbionts has sparked considerable debate regarding their role in facilitating MPB attack success. We tested the hypothesis that MPB ophiostomatoid fungal associates like Grosmannia clavigera (Robinson-Jeffrey and Davidson) Zipfel, de Beer and Wingfield contribute to overwhelming host defenses during MPB mass attack. We compared responses of mature lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) trees growing in natural stands that were mass attacked by MPB with those inoculated with G. clavigera by examining host defense hormones, secondary metabolites, and gene expression profiles. The jasmonate and ethylene signatures of necrotrophic pathogen-triggered response were identified in G. clavigera-inoculated trees, but only the jasmonate signature of a herbivore-triggered response was measured in MPB-attacked trees. Several G. clavigera-induced changes in pine phenolic metabolite profiles and phenolic biosynthesis gene expression patterns were absent in MPB-attacked pines. These findings indicate that ophiostomatoid fungi like G. clavigera are not a major factor in overwhelming host defenses during MPB mass attack. Instead, fungal pathogenicity likely is more important in aiding MPB colonization and development within the host tree. Phenolics appear to play a larger role in the host response to G. clavigera than to MPB, although phenolics may also influence MPB feeding and behavior. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Colleen E Fortier
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Antonia E Musso
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Maya L Evenden
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - L Irina Zaharia
- National Research Council of Canada, Aquatic and Crop Resource Development Research Centre, Saskatoon, SK, S7N 0W9, Canada
| | - Janice E K Cooke
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
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3
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Vazquez-Ortiz K, Pineda-Mendoza RM, González-Escobedo R, Davis TS, Salazar KF, Rivera-Orduña FN, Zúñiga G. Metabarcoding of mycetangia from the Dendroctonus frontalis species complex (Curculionidae: Scolytinae) reveals diverse and functionally redundant fungal assemblages. Front Microbiol 2022; 13:969230. [PMID: 36187976 PMCID: PMC9524821 DOI: 10.3389/fmicb.2022.969230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/18/2022] [Indexed: 11/13/2022] Open
Abstract
Dendroctonus-bark beetles are associated with microbes that can detoxify terpenes, degrade complex molecules, supplement and recycle nutrients, fix nitrogen, produce semiochemicals, and regulate ecological interactions between microbes. Females of some Dendroctonus species harbor microbes in specialized organs called mycetangia; yet little is known about the microbial diversity contained in these structures. Here, we use metabarcoding to characterize mycetangial fungi from beetle species in the Dendroctonus frontalis complex, and analyze variation in biodiversity of microbial assemblages between beetle species. Overall fungal diversity was represented by 4 phyla, 13 classes, 25 orders, 39 families, and 48 genera, including 33 filamentous fungi, and 15 yeasts. The most abundant genera were Entomocorticium, Candida, Ophiostoma-Sporothrix, Ogataea, Nakazawaea, Yamadazyma, Ceratocystiopsis, Grosmannia-Leptographium, Absidia, and Cyberlindnera. Analysis of α-diversity indicated that fungal assemblages of D. vitei showed the highest richness and diversity, whereas those associated with D. brevicomis and D. barberi had the lowest richness and diversity, respectively. Analysis of β-diversity showed clear differentiation in the assemblages associated with D. adjunctus, D. barberi, and D. brevicomis, but not between closely related species, including D. frontalis and D. mesoamericanus and D. mexicanus and D. vitei. A core mycobiome was not statistically identified; however, the genus Ceratocystiopsis was shared among seven beetle species. Interpretation of a tanglegram suggests evolutionary congruence between fungal assemblages and species of the D. frontalis complex. The presence of different amplicon sequence variants (ASVs) of the same genus in assemblages from species of the D. frontalis complex outlines the complexity of molecular networks, with the most complex assemblages identified from D. vitei, D. mesoamericanus, D. adjunctus, and D. frontalis. Analysis of functional variation of fungal assemblages indicated multiple trophic groupings, symbiotroph/saprotroph guilds represented with the highest frequency (∼31% of identified genera). These findings improve our knowledge about the diversity of mycetangial communities in species of the D. frontalis complex and suggest that minimal apparently specific assemblages are maintained and regulated within mycetangia.
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Affiliation(s)
- Karina Vazquez-Ortiz
- Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Rosa María Pineda-Mendoza
- Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Román González-Escobedo
- Laboratorio de Microbiología, Facultad de Zootecnia y Ecología, Universidad Autónoma de Chihuahua, Chihuahua, Mexico
| | - Thomas S. Davis
- Department of Forest and Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO, United States
| | - Kevin F. Salazar
- Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Flor N. Rivera-Orduña
- Laboratorio de Ecología Microbiana, Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
- *Correspondence: Flor N. Rivera-Orduña,
| | - Gerardo Zúñiga
- Laboratorio de Variación Biológica y Evolución, Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
- Gerardo Zúñiga,
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Tian H, Koski TM, Zhao L, Liu Z, Sun J. Invasion History of the Pinewood Nematode Bursaphelenchus xylophilus Influences the Abundance of Serratia sp. in Pupal Chambers and Tracheae of Insect-Vector Monochamus alternatus. FRONTIERS IN PLANT SCIENCE 2022; 13:856841. [PMID: 35668811 PMCID: PMC9164154 DOI: 10.3389/fpls.2022.856841] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/30/2022] [Indexed: 06/01/2023]
Abstract
Pine wilt disease (PWD) has caused extensive mortality in pine forests worldwide. This disease is a result of a multi-species interaction among an invasive pinewood nematode (PWN) Bursaphelenchus xylophilus, its vector Monochamus sp. beetle, and the host pine tree (Pinus sp.). In other systems, microbes have been shown to attenuate negative impacts on invasive species after the invasion has reached a certain time point. Despite that the role of PWD associated microbes involved in the PWD system has been widely studied, it is not known whether similar antagonistic "hidden microbial players" exist in this system due to the lack of knowledge about the potential temporal changes in the composition of associated microbiota. In this study, we investigated the bacteria-to-fungi ratio and isolated culturable bacterial isolates from pupal chambers and vector beetle tracheae across five sampling sites in China differing in the duration of PWN invasion. We also tested the pathogenicity of two candidate bacteria strains against the PWN-vector beetle complex. A total of 118 bacterial species belonging to 4 phyla, 30 families, and 54 genera were classified based on 16S sequencing. The relative abundance of the genus Serratia was lower in pupal chambers and tracheae in newly PWN invaded sites (<10 years) compared to the sites that had been invaded for more than 20 years. Serratia marcescens strain AHPC29 was widely distributed across all sites and showed nematicidal activity against PWN. The insecticidal activity of this strain was dependent on the life stage of the vector beetle Monochamus alternatus: no insecticidal activity was observed against final-instar larvae, whereas S. marcescens was highly virulent against pupae. Our findings improved the understanding of the temporal variation in the microbial community associated with the PWN-vector beetle complex and the progress of PWD and can therefore facilitate the development of biological control agents against PWN and its vector beetle.
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Affiliation(s)
- Haokai Tian
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Tuuli-Marjaana Koski
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Lilin Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Ziying Liu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jianghua Sun
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- College of Life Science, Institute of Life Science and Green Development, Hebei University, Baoding, China
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5
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Zhang X, Li Y, Si H, Zhao G, Kolařík M, Hulcr J, Jiang X, Dai M, Chang R. Geosmithia Species Associated With Bark Beetles From China, With the Description of Nine New Species. Front Microbiol 2022; 13:820402. [PMID: 35369427 PMCID: PMC8964297 DOI: 10.3389/fmicb.2022.820402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/11/2022] [Indexed: 11/23/2022] Open
Abstract
Fungi of the genus Geosmithia are frequently associated with bark beetles that feed on phloem on various woody hosts. Most studies on Geosmithia were carried out in North and South America and Europe, with only two species being reported from Taiwan, China. This study aimed to investigate the diversity of Geosmithia species in China. Field surveys in Fujian, Guangdong, Guangxi, Hunan, Jiangsu, Jiangxi, Shandong, Shanghai, and Yunnan yielded a total of 178 Geosmithia isolates from 12 beetle species. The isolates were grouped based on morphology. The internal transcribed spacer, β-tubulin, and elongation factor 1-α gene regions of the representatives of each group were sequenced. Phylogenetic trees were constructed based on those sequences. In total, 12 species were identified, with three previously described species (Geosmithia xerotolerans, G. putterillii, and G. pallida) and nine new species which are described in this paper as G. luteobrunnea, G. radiata, G. brevistipitata, G. bombycina, G. granulata (Geosmithia sp. 20), G. subfulva, G. pulverea (G. sp. 3 and Geosmithia sp. 23), G. fusca, and G. pumila sp. nov. The dominant species obtained in this study were G. luteobrunnea and G. pulverea. This study systematically studied the Geosmithia species in China and made an important contribution to filling in the gaps in our understanding of global Geosmithia species diversity.
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Affiliation(s)
- Xiuyu Zhang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - You Li
- Vector-Borne Virus Research Center, Fujian Province Key Laboratory of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.,College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China.,School of Forests, Fisheries and Geomatics Sciences, University of Florida, Gainesville, FL, United States
| | - Hongli Si
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Guoyan Zhao
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Miroslav Kolařík
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czechia
| | - Jiri Hulcr
- School of Forests, Fisheries and Geomatics Sciences, University of Florida, Gainesville, FL, United States
| | - Xiaoqian Jiang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Meixue Dai
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Runlei Chang
- College of Life Sciences, Shandong Normal University, Jinan, China
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6
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Knaden M, Anderson P, Andersson MN, Hill SR, Sachse S, Sandgren M, Stensmyr MC, Löfstedt C, Ignell R, Hansson BS. Human Impacts on Insect Chemical Communication in the Anthropocene. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.791345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The planet is presently undergoing dramatic changes caused by human activities. We are living in the era of the Anthropocene, where our activities directly affect all living organisms on Earth. Insects constitute a major part of the world’s biodiversity and currently, we see dwindling insect biomass but also outbreaks of certain populations. Most insects rely on chemical communication to locate food, mates, and suitable oviposition sites, but also to avoid enemies and detrimental microbes. Emissions of, e.g., CO2, NOx, and ozone can all affect the chemical communication channel, as can a rising temperature. Here, we present a review of the present state of the art in the context of anthropogenic impact on insect chemical communication. We concentrate on present knowledge regarding fruit flies, mosquitoes, moths, and bark beetles, as well as presenting our views on future developments and needs in this emerging field of research. We include insights from chemical, physiological, ethological, and ecological directions and we briefly present a new international research project, the Max Planck Centre for Next Generation Insect Chemical Ecology (nGICE), launched to further increase our understanding of the impact of human activities on insect olfaction and chemical communication.
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7
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Diversity and Evolution of Entomocorticium (Russulales, Peniophoraceae), a Genus of Bark Beetle Mutualists Derived from Free-Living, Wood Rotting Peniophora. J Fungi (Basel) 2021; 7:jof7121043. [PMID: 34947025 PMCID: PMC8706356 DOI: 10.3390/jof7121043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 11/17/2022] Open
Abstract
Symbiosis between insects and fungi arose multiple times during the evolution of both groups, and some of the most biologically diverse and economically important are mutualisms in which the insects cultivate and feed on fungi. Among these are bark beetles, whose ascomycetous cultivars are better known and studied than their frequently-overlooked and poorly understood basidiomycetous partners. In this study, we propose five new species of Entomocorticium, fungal mutualists in the Russulales (Basidiomycota) that are mutualistic symbionts of scolytine beetles. We have isolated these fungi from the beetle mycangia, which are structures adapted for the selective storage and transportation of fungal mutualists. Herein, we present the most complete phylogeny of the closely related genera Entomocorticium and Peniophora and provide insights into how an insect-associated taxon (Entomocorticium) evolved from within a wood-decaying, wind-dispersed lineage (Peniophora). Our results indicate that following a transition from angiosperms to gymnosperms, fungal domestication by beetles facilitated the evolution and diversification of Entomocorticium. We additionally propose four new species: Entomocorticium fibulatum Araújo, Li & Hulcr, sp. nov.; E. belizense Araújo, Li & Hulcr, sp. nov.; E. perryae Araújo, Li & Hulcr, sp. nov.; and E. macrovesiculatum Araújo, Li, Six & Hulcr, sp. nov. Our findings highlight the fact that insect-fungi associations remain an understudied field and that these associations harbor a large reservoir of novel fungal species.
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Niinemets Ü, Gershenzon J. Vulnerability and responses to bark beetle and associated fungal symbiont attacks in conifers. TREE PHYSIOLOGY 2021; 41:1103-1108. [PMID: 33949675 DOI: 10.1093/treephys/tpab064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/19/2020] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Ülo Niinemets
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51006, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
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9
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Peris D, Delclòs X, Jordal B. Origin and evolution of fungus farming in wood-boring Coleoptera - a palaeontological perspective. Biol Rev Camb Philos Soc 2021; 96:2476-2488. [PMID: 34159702 DOI: 10.1111/brv.12763] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/02/2021] [Accepted: 06/04/2021] [Indexed: 12/11/2022]
Abstract
Insect-fungus mutualism is one of the better-studied symbiotic interactions in nature. Ambrosia fungi are an ecological assemblage of unrelated fungi that are cultivated by ambrosia beetles in their galleries as obligate food for larvae. Despite recently increased research interest, it remains unclear which ecological factors facilitated the origin of fungus farming, and how it transformed into a symbiotic relationship with obligate dependency. It is clear from phylogenetic analyses that this symbiosis evolved independently many times in several beetle and fungus lineages. However, there is a mismatch between palaeontological and phylogenetic data. Herein we review, for the first time, the ambrosia system from a palaeontological perspective. Although largely ignored, families such as Lymexylidae and Bostrichidae should be included in the list of ambrosia beetles because some of their species cultivate ambrosia fungi. The estimated origin for some groups of ambrosia fungi during the Cretaceous concurs with a known high diversity of Lymexylidae and Bostrichidae at that time. Although potentially older, the greatest radiation of various ambrosia beetle lineages occurred in the weevil subfamilies Scolytinae and Platypodinae during the Eocene. In this review we explore the evolutionary relationship between ambrosia beetles, fungi and their host trees, which is likely to have persisted for longer than previously supposed.
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Affiliation(s)
- David Peris
- Institute of Geosciences, University of Bonn, Nussallee 8, Bonn, 53115, Germany.,Department of Earth and Ocean Dynamics, Faculty of Earth Sciences, University of Barcelona, Martí i Franquès s/n, Barcelona, 08028, Spain
| | - Xavier Delclòs
- Department of Earth and Ocean Dynamics, Faculty of Earth Sciences, University of Barcelona, Martí i Franquès s/n, Barcelona, 08028, Spain.,Biodiversity Research Institute (IRBio), University of Barcelona, Avinguda Diagonal 643, Barcelona, 08028, Spain
| | - Bjarte Jordal
- Museum of Natural History, University Museum of Bergen, University of Bergen, Haakon Sheteligs plass 10, Bergen, N-5007, Norway
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Six DL, Klepzig KD. Context Dependency in Bark Beetle-Fungus Mutualisms Revisited: Assessing Potential Shifts in Interaction Outcomes Against Varied Genetic, Ecological, and Evolutionary Backgrounds. Front Microbiol 2021; 12:682187. [PMID: 34054789 PMCID: PMC8149605 DOI: 10.3389/fmicb.2021.682187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
Context dependency occurs when biological interactions shift in sign or magnitude depending upon genetic, abiotic, and biotic context. Most models of mutualism address systems where interaction outcomes slide along a mutualism-antagonism continuum as environmental conditions vary altering cost-benefit relationships. However, these models do not apply to the many mutualisms that involve by-product benefits and others that do not have antagonistic alternate states. The ubiquity of such mutualisms indicates a need for different approaches and models to understand how environmental variability influences their strength, stability, and ecological roles. In this paper, we apply the concept of context dependency to mutualisms among bark beetles and fungi that span a variety of life strategies and exposures to environmental variability. Bark beetles and their mutualist fungi co-construct a niche based on by-product benefits that allows them to exist in a resource that is otherwise intractable or inaccessible. For the closest of these partnerships, this has resulted in some of the most influential agents of forest mortality in conifer forests worldwide. Understanding these symbioses is key to understanding their influence on forest structure and dynamics and responses to change. We found no evidence that bark beetle mutualisms change in sign as conditions vary, only in magnitude, and that the "closest" (and most environmentally influential) of these partnerships have evolved behaviors and mechanisms to reduce context-dependency and stabilize benefit delivery. The bark beetle-fungus symbioses most likely to slide along a mutualism-antagonism continuum are those involving loosely associated facultative symbionts that may provide benefits under some circumstances and that are horizontally transmitted by the beetle host. Additionally, some symbiotic fungi are never mutualists - these "third party" fungi are exploiters and may shift from commensalism to antagonism depending on environmental context. Our assessment indicates that a careful differentiation between bark beetle-fungus partnerships is crucial to understanding how they influence forests and respond to environmental variability.
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Affiliation(s)
- Diana L Six
- Department of Ecosystem and Conservation Science, The University of Montana, Missoula, MT, United States
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11
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Nuotclà JA, Diehl JMC, Taborsky M. Habitat Quality Determines Dispersal Decisions and Fitness in a Beetle – Fungus Mutualism. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.602672] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Delayed dispersal of sexually mature offspring is a fundamental component of cooperative breeding. In ambrosia beetles, female offspring temporarily remain in their natal nest and refrain from reproduction, instead investing in alloparental care. Previous work has demonstrated a link between helping behaviour and the increased need for pathogen defence, arising from their close association with fungal cultivars. In the ambrosia beetle Xyleborinus saxesenii, mature female offspring can effectively fight pathogen infections and manage the microbial composition within the nest by adjusting the frequency of different hygienic and nest maintenance behaviours. This suggests a potential to respond flexibly to the ecology of their nest, which calls for a better understanding of the connection between behaviour and the microbial community thriving within their nests. Here, we studied the significance of the mutualistic fungus garden composition for the beetles’ nest ecology and fitness by experimentally varying substrate quality. We found that the vertically transmitted ambrosia fungus garden is composed of at least two fungus mutualist species and a wide variety of other microbes varying in their relative abundance. This is strongly affected by the moisture content of the substrate, which in nature depends on the age and type of wood. We found that the mutualist fungi complement each other in terms of dryness-resistance, allowing the beetles to utilise a broad range of substrates over prolonged time during which the wood gradually desiccates. Under suboptimal humidity conditions, the interaction between host and multiple fungus species has important ramifications for the behaviour of philopatric helpers, including their alloparental investment, sibling cannibalism and the timing of dispersal. Rearing five generations of beetles consecutively in dry substrate resulted in transgenerational effects on philopatry and alloparental care, probably mediated through the dominance of a particular fungus species that was driven by the experimental habitat condition. Interestingly, the nests of these selection lines produced much more offspring after five generations than any first-generation nest, which may have reflected increased egg laying by non-dispersing daughters. Our study highlights the importance of considering the interactions between the microbial community and their insect hosts for understanding social evolution in cooperatively breeding beetles.
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12
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Field Translocation of Mountain Pine Beetles Suggests Phoretic Mite Communities Are Locally Adapted, and Mite Populations Respond Variably to Climate Warming. INSECTS 2021; 12:insects12020131. [PMID: 33540901 PMCID: PMC7913132 DOI: 10.3390/insects12020131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 11/17/2022]
Abstract
Simple Summary Climate warming has significant effects on forest insect populations, particularly bark beetles, which cause millions of hectares of forest tree damage. Bark beetles live alongside a diverse host of other organisms which affect the success of beetle attacks on trees and are also affected by climate changes. Here, we explore climate effects on symbiotic mite communities associated with the mountain pine beetle (Dendroctonus ponderosae). We show that warming causes significant shifts in the abundance of mites. These effects were dependent on source population, suggesting mite populations are adapted to their local climates. Understanding beetle–mite patterns is important because mites can directly affect beetle reproduction by feeding on eggs, or indirectly affect beetle health by introducing fungi. Our results provide foundational information for understanding how climate change will affect beetle–mite associations; and serve to help determine how these shifting associations will affect the success of bark beetles in forest ecosystems. Abstract Temperature is a key determining factor in the population dynamics of forest insects and their associated biota. Bark beetles, often considered key agents of change in forest ecosystems, are particularly affected by warming in their environment. Beetles associate with various phoretic mite species that have direct/indirect effects on beetle fitness and population dynamics, although there is limited knowledge of how temperature affects these communities. Here, we use a field reciprocal translocation experiment with the addition of a novel “warming” environment to represent future changes in local environment in two populations of a keystone bark beetle species (Dendroctonus ponderosae). We hypothesize that mite community abundances as carried by bark beetles are significantly altered when not in their native environments and when subjected to climate warming. We use multivariate generalized linear models based on species abundance data to show that mite community compositions significantly differ across different field climates; and that these patterns diverge between source populations, indicating local adaptation. Our study offers foundational information on the general effects of simulated climate-warming on the compositional shifts of common and abundant biotic associates of mountain pine beetles and may be used as a model system for other important insect–mite systems.
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Soderberg DN, Mock KE, Hofstetter RW, Bentz BJ. Translocation experiment reveals capacity for mountain pine beetle persistence under climate warming. ECOL MONOGR 2020. [DOI: 10.1002/ecm.1437] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- David N. Soderberg
- Wildland Resources Department Utah State University 5230 Old Main Hill Logan Utah84322USA
- Ecology Center Utah State University 5205 Old Main Hill Logan Utah84322USA
| | - Karen E. Mock
- Wildland Resources Department Utah State University 5230 Old Main Hill Logan Utah84322USA
- Ecology Center Utah State University 5205 Old Main Hill Logan Utah84322USA
| | - Richard W. Hofstetter
- School of Forestry College of Engineering, Forestry and Natural Sciences Northern Arizona University Flagstaff Arizona86011USA
| | - Barbara J. Bentz
- Wildland Resources Department Utah State University 5230 Old Main Hill Logan Utah84322USA
- U.S. Forest Service Rocky Mountain Research Station 860 N. 1200 E Logan Utah84321USA
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Mbenoun M, Wingfield MJ, Misse AC, Roux J. Selective feeding behaviors illuminate patterns of sap beetle associations with ophiostomatoid fungi. Symbiosis 2020. [DOI: 10.1007/s13199-020-00705-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Guevara-Rozo S, Hussain A, Cale JA, Klutsch JG, Rajabzadeh R, Erbilgin N. Nitrogen and Ergosterol Concentrations Varied in Live Jack Pine Phloem Following Inoculations With Fungal Associates of Mountain Pine Beetle. Front Microbiol 2020; 11:1703. [PMID: 32793164 PMCID: PMC7390957 DOI: 10.3389/fmicb.2020.01703] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/29/2020] [Indexed: 01/14/2023] Open
Abstract
Bark beetles form symbiotic associations with multiple species of fungi that supplement their metabolic needs. However, the relative contributions of each symbiont to the nutrition of bark beetles have been largely unexplored. Thus, we evaluated the ability of three fungal symbionts of mountain pine beetle to concentrate nitrogen and produce ergosterol while infecting phloem of a novel host jack pine. Ergosterol was used as proxy to determine the fungal biomass (hyphal density) in the current study. We inoculated 80 trees in two forest stands with one of the three fungal species or a non-fungal (control) agar. Six weeks later, we collected phloem from the necrotic lesions induced by the fungi, uninfected tissues adjacent to lesions, and non-inoculated control trees. We found that nutritional contributions varied with fungal species. Nitrogen in lesions was higher in trees inoculated with Ophiostoma montium or control trees, relative to Grosmannia clavigera or Leptographium longiclavatum. Furthermore, concentrations of ergosterol were higher in O. montium lesions compared to other tissues or treatments. These results suggest that O. montium differs from G. clavigera and L. longiclavatum in terms of acquiring nitrogen from host tissues and producing ergosterol.
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Affiliation(s)
- Sydne Guevara-Rozo
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Altaf Hussain
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Jonathan A Cale
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
| | | | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada
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Six DL. Niche construction theory can link bark beetle-fungus symbiosis type and colonization behavior to large scale causal chain-effects. CURRENT OPINION IN INSECT SCIENCE 2020; 39:27-34. [PMID: 32114295 DOI: 10.1016/j.cois.2019.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/16/2019] [Accepted: 12/21/2019] [Indexed: 06/10/2023]
Abstract
Bark beetles form a variety of symbioses with fungi. Recent studies reveal how the fungi influence beetle nutrition and detoxify tree defenses and provide insight into why these symbioses vary so greatly in their outcomes, not only for host and symbiont, but also for the forest ecosystems within which they exist. Here, I review recent advances in our knowledge of these systems. I then introduce how niche construction theory can provide a framework to use this knowledge to better understand how different symbiosis types result in a gradient of ecosystem effects ranging from massive and durable to those of little ecological consequence.
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Affiliation(s)
- Diana L Six
- Department of Ecosystem and Conservation Sciences, University of Montana, Missoula, MT 59804, USA.
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Lemoine MM, Engl T, Kaltenpoth M. Microbial symbionts expanding or constraining abiotic niche space in insects. CURRENT OPINION IN INSECT SCIENCE 2020; 39:14-20. [PMID: 32086000 DOI: 10.1016/j.cois.2020.01.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 05/06/2023]
Abstract
In addition to their well-studied contributions to their host's nutrition, digestion, and defense, microbial symbionts of insects are increasingly found to affect their host's response toward abiotic stressors. In particular, symbiotic microbes can reduce or enhance tolerance to temperature extremes, improve desiccation resistance by aiding cuticle biosynthesis and sclerotization, and detoxify heavy metals. As such, individual symbionts or microbial communities can expand or constrain the abiotic niche space of their host and determine its adaptability to fluctuating environments. In light of the increasing impact of humans on climate and environment, a better understanding of host-microbe interactions is necessary to predict how different insect species will respond to changes in abiotic conditions.
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Affiliation(s)
- Marion M Lemoine
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Tobias Engl
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany.
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Simler-Williamson AB, Rizzo DM, Cobb RC. Interacting Effects of Global Change on Forest Pest and Pathogen Dynamics. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2019. [DOI: 10.1146/annurev-ecolsys-110218-024934] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Pathogens and insect pests are important drivers of tree mortality and forest dynamics, but global change has rapidly altered or intensified their impacts. Predictive understanding of changing disease and outbreak occurrence has been limited by two factors: ( a) tree mortality and morbidity are emergent phenomena determined by interactions between plant hosts, biotic agents (insects or pathogens), and the environment; and ( b) disparate global change drivers co-occur, obscuring net impacts on each of these components. To expand our understanding of changing forest diseases, declines, and outbreaks, we adopt a framework that identifies and organizes observed impacts of diverse global change drivers on the primary mechanisms underlying agent virulence and host susceptibility. We then discuss insights from ecological theory that may advance prediction of forest epidemics and outbreaks. This approach highlights key drivers of changing pest and pathogen dynamics, which may inform forest management aimed at mitigating accelerating rates of tree mortality globally.
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Affiliation(s)
| | - David M. Rizzo
- Department of Plant Pathology, University of California, Davis, California 95616, USA;,
| | - Richard C. Cobb
- Department of Natural Resources Management and Environmental Science, California Polytechnic State University, San Luis Obispo, California 93407, USA
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Xyleborus volvulus (Coleoptera: Curculionidae): Biology and Fungal Associates. Appl Environ Microbiol 2019; 85:AEM.01190-19. [PMID: 31375485 DOI: 10.1128/aem.01190-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 07/23/2019] [Indexed: 11/20/2022] Open
Abstract
The ambrosia beetle Xyleborus volvulus Fabricius has been reported as a potential vector of the plant pathogen Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva that is affecting avocado orchards in South Florida. In this study, we examined its life cycle, process of gallery formation, gallery structure, and fungal associates by rearing one generation on avocado sawdust medium under control conditions. The adult foundress excavated a vertical tunnel that constituted the main gallery with a length of 2.5 cm, followed by the construction of up to six secondary galleries with a total length of 4.4 cm. The time period for one generation (egg to adult) was 28 days. Teneral males emerged 3 days after the emergence of the first females. The F1 generation did not significantly contribute to gallery expansion. Four species of Raffaelea and nine yeast species were recovered from galleries and beetles. Raffaelea arxii and Candida berthetii were the most frequent symbionts recovered from new adults and galleries. Candida berthetii dominated during the early stages of the gallery development, whereas R. arxii was most frequent in later stages. Other Raffaelea species were inconsistently isolated from galleries, which suggests a strong association between Xyleborus volvulus and both R. arxii and C. berthetii These results suggest that R. arxii is the primary nutritional symbiont of X. volvulus and that yeast species may be pioneer colonizers that assist with the growth of fungal symbionts.IMPORTANCE Ambrosia beetles cultivate fungi in tunnels bored into weakened host trees. This obligate interaction is required for their survival as beetles feed on these symbiotic fungi, and the fungi benefit from transportation by the beetles. Xyleborus volvulus carries many nonpathogenic symbionts; however, recently the acquisition of Raffaelea lauricola (the causal agent of a lethal vascular disease of lauraceous trees) by this beetle has altered its status from wood degrader to potential pest in avocado. We conducted a study to understand the relationship of this beetle and its fungal associates. Our results show that X. volvulus has a multipartite flexible association with different Raffaelea species. The lack of fidelity in the mutualistic association may explain the acquisition of R. lauricola Knowing the beetle biology and its mutualistic interactions furthers an understanding of the beetle's role as a potential vector and in disease transmission.
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Huang YT, Skelton J, Johnson AJ, Kolařík M, Hulcr J. Geosmithia species in southeastern USA and their affinity to beetle vectors and tree hosts. FUNGAL ECOL 2019. [DOI: 10.1016/j.funeco.2019.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Blaz J, Barrera-Redondo J, Vázquez-Rosas-Landa M, Canedo-Téxon A, Aguirre von Wobeser E, Carrillo D, Stouthamer R, Eskalen A, Villafán E, Alonso-Sánchez A, Lamelas A, Ibarra-Juarez LA, Pérez-Torres CA, Ibarra-Laclette E. Genomic Signals of Adaptation towards Mutualism and Sociality in Two Ambrosia Beetle Complexes. Life (Basel) 2018; 9:E2. [PMID: 30583535 PMCID: PMC6463014 DOI: 10.3390/life9010002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/08/2018] [Accepted: 12/20/2018] [Indexed: 01/03/2023] Open
Abstract
Mutualistic symbiosis and eusociality have developed through gradual evolutionary processes at different times in specific lineages. Like some species of termites and ants, ambrosia beetles have independently evolved a mutualistic nutritional symbiosis with fungi, which has been associated with the evolution of complex social behaviors in some members of this group. We sequenced the transcriptomes of two ambrosia complexes (Euwallacea sp. near fornicatus⁻Fusarium euwallaceae and Xyleborus glabratus⁻Raffaelea lauricola) to find evolutionary signatures associated with mutualism and behavior evolution. We identified signatures of positive selection in genes related to nutrient homeostasis; regulation of gene expression; development and function of the nervous system, which may be involved in diet specialization; behavioral changes; and social evolution in this lineage. Finally, we found convergent changes in evolutionary rates of proteins across lineages with phylogenetically independent origins of sociality and mutualism, suggesting a constrained evolution of conserved genes in social species, and an evolutionary rate acceleration related to changes in selective pressures in mutualistic lineages.
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Affiliation(s)
- Jazmín Blaz
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
| | - Josué Barrera-Redondo
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México 04500, Mexico.
| | | | - Anahí Canedo-Téxon
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
| | | | - Daniel Carrillo
- Tropical Research and Education Center, University of Florida, Homestead, FL 33031, USA.
| | - Richard Stouthamer
- Department of Plant Pathology, University of California⁻Riverside, Riverside, CA 92521, USA.
| | - Akif Eskalen
- Department of Plant Pathology, University of California, Davis, CA 95616-8751, USA.
| | - Emanuel Villafán
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
| | - Alexandro Alonso-Sánchez
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
| | - Araceli Lamelas
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
| | - Luis Arturo Ibarra-Juarez
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
- Cátedras CONACyT/Instituto de Ecología A.C., Xalapa, Veracruz 91070, Mexico.
| | - Claudia Anahí Pérez-Torres
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
- Cátedras CONACyT/Instituto de Ecología A.C., Xalapa, Veracruz 91070, Mexico.
| | - Enrique Ibarra-Laclette
- Red de Estudios Moleculares Avanzados, Instituto de Ecología A.C, Xalapa, Veracruz 91070, Mexico.
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Saucedo-Carabez JR, Ploetz RC, Konkol JL, Carrillo D, Gazis R. Partnerships Between Ambrosia Beetles and Fungi: Lineage-Specific Promiscuity Among Vectors of the Laurel Wilt Pathogen, Raffaelea lauricola. MICROBIAL ECOLOGY 2018; 76:925-940. [PMID: 29675704 DOI: 10.1007/s00248-018-1188-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/10/2018] [Indexed: 05/25/2023]
Abstract
Nutritional mutualisms that ambrosia beetles have with fungi are poorly understood. Although these interactions were initially thought to be specific associations with a primary symbiont, there is increasing evidence that some of these fungi are associated with, and move among, multiple beetle partners. We examined culturable fungi recovered from mycangia of ambrosia beetles associated with trees of Persea humilis (silk bay, one site) and P. americana (avocado, six commercial orchards) that were affected by laurel wilt, an invasive disease caused by a symbiont, Raffaelea lauricola, of an Asian ambrosia beetle, Xyleborus glabratus. Fungi were isolated from 20 adult females of X. glabratus from silk bay and 70 each of Xyleborus affinis, Xyleborus bispinatus, Xyleborus volvulus, Xyleborinus saxesenii, and Xylosandrus crassiusculus from avocado. With partial sequences of ribosomal (LSU and SSU) and nuclear (β-tubulin) genes, one to several operational taxonomic units (OTUs) of fungi were identified in assayed individuals. Distinct populations of fungi were recovered from each of the examined beetle species. Raffaelea lauricola was present in all beetles except X. saxesenii and X. crassiusculus, and Raffaelea spp. predominated in Xyleborus spp. Raffaelea arxii, R. subalba, and R. subfusca were present in more than a single species of Xyleborus, and R. arxii was the most abundant symbiont in both X. affinis and X. volvulus. Raffaelea aguacate was detected for the first time in an ambrosia beetle (X. bispinatus). Yeasts (Ascomycota, Saccharomycotina) were found consistently in the mycangia of the examined beetles, and distinct, putatively co-adapted populations of these fungi were associated with each beetle species. Greater understandings are needed for how mycangia in ambrosia beetles interact with fungi, including yeasts which play currently underresearched roles in these insects.
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Affiliation(s)
- J R Saucedo-Carabez
- Tropical Research & Education Center, University of Florida, Homestead, FL, 33031-3314, USA
| | - Randy C Ploetz
- Tropical Research & Education Center, University of Florida, Homestead, FL, 33031-3314, USA.
| | - J L Konkol
- Tropical Research & Education Center, University of Florida, Homestead, FL, 33031-3314, USA
| | - D Carrillo
- Tropical Research & Education Center, University of Florida, Homestead, FL, 33031-3314, USA
| | - R Gazis
- Tropical Research & Education Center, University of Florida, Homestead, FL, 33031-3314, USA
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Ophiostomatoid fungi associated with the spruce bark beetle Ips typographus, including 11 new species from China. Persoonia - Molecular Phylogeny and Evolution of Fungi 2018; 42:50-74. [PMID: 31551614 PMCID: PMC6712535 DOI: 10.3767/persoonia.2019.42.03] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/31/2018] [Indexed: 11/25/2022]
Abstract
Ips typographus (Coleoptera, Scolytinae) is a spruce-infesting bark beetle that occurs throughout Europe and Asia. The beetle can cause considerable damage, especially when colonized trees are stressed and beetle populations increase. Although some studies have shown that populations of I. typographus in Europe, China and Japan are genetically distinct, these populations are biologically similar, including a strong association with ophiostomatoid fungi. To date, only two Leptographium spp. have been reported from the beetle in China, while 40 species have been reported from Europe and 13 from Japan. The aims of this study were to identify the ophiostomatoid fungal associates of I. typographus in north-eastern China, and to determine whether the fungal assemblages reflect the different geographical populations of the beetle. Field surveys in Jilin and Heilongjiang provinces yielded a total of 1 046 fungal isolates from 145 beetles and 178 galleries. Isolates were grouped based on morphology and representatives of each group were identified using DNA sequences of the ribosomal LSU, ITS, β-tubulin, calmodulin and elongation factor 1-α gene regions. A total of 23 species of ophiostomatoid fungi were identified, including 12 previously described species and 11 novel species, all of which are described here. The dominant species were Ophiostoma bicolor, Leptographium taigense and Grosmannia piceiperda D, representing 40.5 %, 27.8 % and 17.8 % of the isolates, respectively. Comparisons of species from China, Europe and Japan are complicated by the fact that some of the European and all the Japanese species were identified based only on morphology. However, assuming that those identifications are correct, five species were shared between Europe, Japan and China, two species were shared between China and Japan, five between Europe and China, and two between Europe and Japan. Consequently, Ips typographus populations in these different geographic areas have different fungal assemblages, suggesting that the majority of these beetle-associations are promiscuous. The results also suggested that the symbionts of the bark beetle do not reflect the population structures of the beetle. The use of fungal symbiont assemblages to infer population structures and invasion history of its vectors should thus be interpreted with circumspection.
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Ito M, Kajimura H. Landscape-scale genetic differentiation of a mycangial fungus associated with the ambrosia beetle, Xylosandrus germanus (Blandford) (Curculionidae:Scolytinae) in Japan. Ecol Evol 2017; 7:9203-9221. [PMID: 29187962 PMCID: PMC5696423 DOI: 10.1002/ece3.3437] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 07/03/2017] [Accepted: 08/03/2017] [Indexed: 11/29/2022] Open
Abstract
In this study, we examined the genetic structures of the ambrosia fungus isolated from mycangia of the scolytine beetle, Xylosandrus germanus to understand their co‐evolutionary relationships. We analyzed datasets of three ambrosia fungus loci (18S rDNA, 28S rDNA, and the β‐tubulin gene) and a X. germanus locus dataset (cytochrome c oxidase subunit 1 (COI) mitochondrial DNA). The ambrosia fungi were separated into three cultural morphptypes, and their haplotypes were distinguished by phylogenetic analysis on the basis of the three loci. The COI phylogenetic analysis revealed three distinct genetic lineages (clades A, B, and C) within X. germanus, each of which corresponded to specific ambrosia fungus cultural morphptypes. The fungal symbiont phylogeny was not concordant with that of the beetle. Our results suggest that X. germanus may be unable to exchange its mycangial fungi, but extraordinary horizontal transmission of symbiotic fungi between the beetle's lineages occurred at least once during the evolutionary history of this symbiosis.
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Affiliation(s)
- Masaaki Ito
- Graduate School of Bioagricultural Sciences Nagoya University Nagoya Japan
| | - Hisashi Kajimura
- Graduate School of Bioagricultural Sciences Nagoya University Nagoya Japan
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Ojeda Alayon DI, Tsui CKM, Feau N, Capron A, Dhillon B, Zhang Y, Massoumi Alamouti S, Boone CK, Carroll AL, Cooke JEK, Roe AD, Sperling FAH, Hamelin RC. Genetic and genomic evidence of niche partitioning and adaptive radiation in mountain pine beetle fungal symbionts. Mol Ecol 2017; 26:2077-2091. [PMID: 28231417 DOI: 10.1111/mec.14074] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 12/08/2016] [Accepted: 02/09/2017] [Indexed: 12/19/2022]
Abstract
Bark beetles form multipartite symbiotic associations with blue stain fungi (Ophiostomatales, Ascomycota). These fungal symbionts play an important role during the beetle's life cycle by providing nutritional supplementation, overcoming tree defences and modifying host tissues to favour brood development. The maintenance of stable multipartite symbioses with seemingly less competitive symbionts in similar habitats is of fundamental interest to ecology and evolution. We tested the hypothesis that the coexistence of three fungal species associated with the mountain pine beetle is the result of niche partitioning and adaptive radiation using SNP genotyping coupled with genotype-environment association analysis and phenotypic characterization of growth rate under different temperatures. We found that genetic variation and population structure within each species is best explained by distinct spatial and environmental variables. We observed both common (temperature seasonality and the host species) and distinct (drought, cold stress, precipitation) environmental and spatial factors that shaped the genomes of these fungi resulting in contrasting outcomes. Phenotypic intraspecific variations in Grosmannia clavigera and Leptographium longiclavatum, together with high heritability, suggest potential for adaptive selection in these species. By contrast, Ophiostoma montium displayed narrower intraspecific variation but greater tolerance to extreme high temperatures. Our study highlights unique phenotypic and genotypic characteristics in these symbionts that are consistent with our hypothesis. By maintaining this multipartite relationship, the bark beetles have a greater likelihood of obtaining the benefits afforded by the fungi and reduce the risk of being left aposymbiotic. Complementarity among species could facilitate colonization of new habitats and survival under adverse conditions.
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Affiliation(s)
- Dario I Ojeda Alayon
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Clement K M Tsui
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Nicolas Feau
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Arnaud Capron
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Braham Dhillon
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Yiyuan Zhang
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Sepideh Massoumi Alamouti
- Department of Wood Science, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Celia K Boone
- Ecosystem Science and Management Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada, V2N 4Z9
| | - Allan L Carroll
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Janice E K Cooke
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada, T6G 2R3
| | - Amanda D Roe
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada, T6G 2R3.,Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St E, Sault Ste. Marie, ON, Canada, P6A 2E5
| | - Felix A H Sperling
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada, T6G 2R3
| | - Richard C Hamelin
- Department of Forest and Conservation Sciences, The University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4.,Institut de Biologie Intégrative des Systèmes, Université Laval, 1030 Avenue de la Médecine, Québec City, QC, Canada, G1V 0A6
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Morris JL, Cottrell S, Fettig CJ, Hansen WD, Sherriff RL, Carter VA, Clear JL, Clement J, DeRose RJ, Hicke JA, Higuera PE, Mattor KM, Seddon AWR, Seppä HT, Stednick JD, Seybold SJ. Managing bark beetle impacts on ecosystems and society: priority questions to motivate future research. J Appl Ecol 2016. [DOI: 10.1111/1365-2664.12782] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jesse L. Morris
- Department of Geography; University of Utah; Salt Lake City UT USA
| | - Stuart Cottrell
- Department of Human Dimensions of Natural Resources; Colorado State University; Fort Collins CO USA
| | - Christopher J. Fettig
- Pacific Southwest Research Station; Invasives and Threats; Ecosystem Function and Health; USDA Forest Service; Davis CA USA
| | | | | | | | - Jennifer L. Clear
- Department of Forest Ecology; Czech University of Life Sciences; Prague Czech Republic
- Department of Marine and Coastal Sciences; Rutgers University; New Brunswick NJ USA
| | - Jessica Clement
- Ruckelshaus Institute of Environment and Natural Resources; University of Wyoming; Laramie WY USA
| | - R. Justin DeRose
- Rocky Mountain Research Station; Forest Inventory and Analysis; USDA Forest Service; Ogden UT USA
| | | | - Philip E. Higuera
- Department of Ecosystem and Conservation Sciences; University of Montana; Missoula MT USA
| | - Katherine M. Mattor
- Department of Human Dimensions of Natural Resources; Colorado State University; Fort Collins CO USA
| | | | - Heikki T. Seppä
- Department of Geosciences and Geography; University of Helsinki; Helsinki Finland
| | - John D. Stednick
- Department of Forest and Rangeland Stewardship; Colorado State University; Fort Collins CO USA
| | - Steven J. Seybold
- Pacific Southwest Research Station; Invasives and Threats; Ecosystem Function and Health; USDA Forest Service; Davis CA USA
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Kandasamy D, Gershenzon J, Hammerbacher A. Volatile Organic Compounds Emitted by Fungal Associates of Conifer Bark Beetles and their Potential in Bark Beetle Control. J Chem Ecol 2016; 42:952-969. [PMID: 27687998 PMCID: PMC5101256 DOI: 10.1007/s10886-016-0768-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/14/2016] [Accepted: 09/07/2016] [Indexed: 11/06/2022]
Abstract
Conifer bark beetles attack and kill mature spruce and pine trees, especially during hot and dry conditions. These beetles are closely associated with ophiostomatoid fungi of the Ascomycetes, including the genera Ophiostoma, Grosmannia, and Endoconidiophora, which enhance beetle success by improving nutrition and modifying their substrate, but also have negative impacts on beetles by attracting predators and parasites. A survey of the literature and our own data revealed that ophiostomatoid fungi emit a variety of volatile organic compounds under laboratory conditions including fusel alcohols, terpenoids, aromatic compounds, and aliphatic alcohols. Many of these compounds already have been shown to elicit behavioral responses from bark beetles, functioning as attractants or repellents, often as synergists to compounds currently used in bark beetle control. Thus, these compounds could serve as valuable new agents for bark beetle management. However, bark beetle associations with fungi are very complex. Beetle behavior varies with the species of fungus, the stage of the beetle life cycle, the host tree quality, and probably with changes in the emission rate of fungal volatiles. Additional research on bark beetles and their symbiotic associates is necessary before the basic significance of ophiostomatoid fungal volatiles can be understood and their applied potential realized.
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Affiliation(s)
- Dineshkumar Kandasamy
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Str. 8, 07745, Jena, Germany
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll Str. 8, 07745, Jena, Germany.
| | - Almuth Hammerbacher
- Department of Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Private Bag X20, Hatfield, Pretoria, 0028, South Africa
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Rassati D, Faccoli M, Haack RA, Rabaglia RJ, Petrucco Toffolo E, Battisti A, Marini L. Bark and Ambrosia Beetles Show Different Invasion Patterns in the USA. PLoS One 2016; 11:e0158519. [PMID: 27459191 PMCID: PMC4961435 DOI: 10.1371/journal.pone.0158519] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/16/2016] [Indexed: 12/02/2022] Open
Abstract
Non-native bark and ambrosia beetles represent a threat to forests worldwide. Their invasion patterns are, however, still unclear. Here we investigated first, if the spread of non-native bark and ambrosia beetles is a gradual or a discontinuous process; second, which are the main correlates of their community structure; third, whether those correlates correspond to those of native species. We used data on species distribution of non-native and native scolytines in the continental 48 USA states. These data were analyzed through a beta-diversity index, partitioned into species richness differences and species replacement, using Mantel correlograms and non-metric multidimensional scaling (NMDS) ordination for identifying spatial patterns, and regression on distance matrices to test the association of climate (temperature, rainfall), forest (cover area, composition), geographical (distance), and human-related (import) variables with β-diversity components. For both non-native bark and ambrosia beetles, β-diversity was mainly composed of species richness difference than species replacement. For non-native bark beetles, a discontinuous invasion process composed of long distance jumps or multiple introduction events was apparent. Species richness differences were primarily correlated with differences in import values while temperature was the main correlate of species replacement. For non-native ambrosia beetles, a more continuous invasion process was apparent, with the pool of non-native species arriving in the coastal areas that tended to be filtered as they spread to interior portions of the continental USA. Species richness differences were mainly correlated with differences in rainfall among states, while rainfall and temperature were the main correlates of species replacement. Our study suggests that the different ecology of bark and ambrosia beetles influences their invasion process in new environments. The lower dependency that bark beetles have on climate allowed them to potentially colonize more areas within the USA, while non-native ambrosia beetles, being dependent on rainfall, are typically filtered by the environment.
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Affiliation(s)
- Davide Rassati
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Legnaro (PD), Italy
| | - Massimo Faccoli
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Legnaro (PD), Italy
| | - Robert A. Haack
- USDA Forest Service, Northern Research Station, Lansing, Michigan, United States of America
| | - Robert J. Rabaglia
- USDA Forest Service, Forest Health Protection, Washington, D. C., United States of America
| | - Edoardo Petrucco Toffolo
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Legnaro (PD), Italy
| | - Andrea Battisti
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Legnaro (PD), Italy
| | - Lorenzo Marini
- Department of Agronomy, Food, Natural Resources, Animals, & Environment (DAFNAE), University of Padua, Legnaro (PD), Italy
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Linnakoski R, Mahilainen S, Harrington A, Vanhanen H, Eriksson M, Mehtätalo L, Pappinen A, Wingfield MJ. Seasonal Succession of Fungi Associated with Ips typographus Beetles and Their Phoretic Mites in an Outbreak Region of Finland. PLoS One 2016; 11:e0155622. [PMID: 27187192 PMCID: PMC4871339 DOI: 10.1371/journal.pone.0155622] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/02/2016] [Indexed: 11/25/2022] Open
Abstract
The ophiostomatoid fungi (Microascales and Ophiostomatales, Ascomycota) are common associates of Ips typographus, and include tree pathogens and species responsible for blue-stain of timber. Fungal assemblages associated with I. typographus have varied considerably between studies but few investigations have attempted to explain this variation. For this reason, we assessed the overall cultivable fungal diversity associated with I. typographus in a storm-felled spruce forest in south-eastern Finland. Fungi were isolated from the individually collected beetles as well as their phoretic mites in spring, summer and autumn, including different life stages of the beetle (hibernation, dispersal flight and first generation). The internal transcribed spacer (ITS) gene region was used to identify the fungi. A total of 32 operational taxonomic units (OTUs) were found and these resided in four fungal phyla/subphyla (24 Ascomycota, 2 Basidiomycota, 5 Mucoromycotina, 1 Mortierellomycotina) in association with adult bark beetles. Ophiostomatoid species were the most commonly detected fungal associates. A generalized linear model analysis showed a clear association between fungal communities and season, indicating seasonal succession among I. typographus-associated fungi. The season of sampling appears to be an important factor that has resulted in inconsistencies between results in previous studies. Many of these fungi were also found on phoretic mites and their presence or absence could have influenced variation in patterns of association.
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Affiliation(s)
- Riikka Linnakoski
- Department of Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
- * E-mail:
| | - Saila Mahilainen
- School of Forest Sciences, Faculty of Science and Forestry, University of Eastern Finland, Joensuu, Finland
| | | | - Henri Vanhanen
- Natural Resources Institute Finland (Luke), Joensuu, Finland
| | - Miikka Eriksson
- School of Applied Educational Science and Teacher Education, Philosophical Faculty, University of Eastern Finland, Savonlinna, Finland
| | - Lauri Mehtätalo
- School of Computing, University of Eastern Finland, Joensuu, Finland
| | - Ari Pappinen
- School of Forest Sciences, Faculty of Science and Forestry, University of Eastern Finland, Joensuu, Finland
| | - Michael J. Wingfield
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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Campbell AS, Ploetz RC, Dreaden TJ, Kendra PE, Montgomery WS. Geographic variation in mycangial communities of Xyleborus glabratus. Mycologia 2016; 108:657-67. [PMID: 27055571 DOI: 10.3852/15-133] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 03/04/2016] [Indexed: 11/10/2022]
Abstract
Factors that influence fungal communities in ambrosia beetle mycangia are poorly understood. The beetle that is responsible for spreading laurel wilt in SE USA, Xyleborus glabratrus, was examined at three sites along a 500 km N-S transect in Florida, each populated by host trees in the Lauraceae. Fungal phenotypes were quantified in mycangia of individual females that were collected from a site in Miami-Dade County (MDC), 25.8N, with swamp bay (Persea palustris), one in Highlands County (HC), 27.9N, with silkbay (P. humulis) and swamp bay and another in Alachua County (AC), 29.8N, with redbay (P. borbonia). Based on combined LSU, SSU and beta-tubulin datasets the most prominent phenotypes were Raffaelea lauricola (cause of laurel wilt), R. subalba, R. subfusca, R. fusca, R. arxii and an undescribed Raffaelea sp. Mean numbers of colony forming units (CFUs) of R. lauricola varied by location (P < 0.003), and a multivariate analysis, which accounted for the presence and relative abundance of fungal species, indicated that there were significant variations in mycangial communities among the sites; thus climate and vegetation might have affected fungal diversity and the relative abundance of these fungi in the mycangia of X. glabratus Statistically it was unlikely that any of the species influenced the presence and prevalence of another species.
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Affiliation(s)
- Alina S Campbell
- University of Florida, Tropical Research & Education Center, Homestead, Florida 33031
| | - Randy C Ploetz
- University of Florida, Tropical Research & Education Center, Homestead, Florida 33031
| | - Tyler J Dreaden
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611Southern Research Station, USDA-Forest Service, Forest Health Research and Education Center, Lexington, Kentucky 40517
| | - Paul E Kendra
- Subtropical Horticulture Research Station, USDA-ARS, Miami, Florida 33158
| | - Wayne S Montgomery
- Subtropical Horticulture Research Station, USDA-ARS, Miami, Florida 33158
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31
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West DR, Briggs JS, Jacobi WR, Negrón JF. Mountain Pine Beetle Host Selection Between Lodgepole and Ponderosa Pines in the Southern Rocky Mountains. ENVIRONMENTAL ENTOMOLOGY 2016; 45:127-141. [PMID: 26546596 DOI: 10.1093/ee/nvv167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/19/2015] [Indexed: 06/05/2023]
Abstract
Recent evidence of range expansion and host transition by mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) has suggested that MPB may not primarily breed in their natal host, but will switch hosts to an alternate tree species. As MPB populations expanded in lodgepole pine forests in the southern Rocky Mountains, we investigated the potential for movement into adjacent ponderosa pine forests. We conducted field and laboratory experiments to evaluate four aspects of MPB population dynamics and host selection behavior in the two hosts: emergence timing, sex ratios, host choice, and reproductive success. We found that peak MPB emergence from both hosts occurred simultaneously between late July and early August, and the sex ratio of emerging beetles did not differ between hosts. In two direct tests of MPB host selection, we identified a strong preference by MPB for ponderosa versus lodgepole pine. At field sites, we captured naturally emerging beetles from both natal hosts in choice arenas containing logs of both species. In the laboratory, we offered sections of bark and phloem from both species to individual insects in bioassays. In both tests, insects infested ponderosa over lodgepole pine at a ratio of almost 2:1, regardless of natal host species. Reproductive success (offspring/female) was similar in colonized logs of both hosts. Overall, our findings suggest that MPB may exhibit equally high rates of infestation and fecundity in an alternate host under favorable conditions.
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Affiliation(s)
- Daniel R West
- Colorado State University, Colorado State Forest Service, 5060 Campus Delivery, Fort Collins, CO 80523-5060 (; ),
| | - Jennifer S Briggs
- U.S. Geological Survey, Geosciences and Environmental Change Science Center, Box 25046, M.S. 980, Bldg., 25, Denver Federal Center, Denver, CO 80225 , and
| | - William R Jacobi
- Colorado State University, Colorado State Forest Service, 5060 Campus Delivery, Fort Collins, CO 80523-5060 (; )
| | - José F Negrón
- USDA Forest Service, Rocky Mountain Research Station, 240 West Prospect, Fort Collins, CO 80525
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32
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Dysthe JC, Bracewell R, Six DL. Temperature effects on growth of fungal symbionts of the western pine beetle, Dendroctonus brevicomis. FUNGAL ECOL 2015. [DOI: 10.1016/j.funeco.2015.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Moore ML, Six DL. Effects of Temperature on Growth, Sporulation, and Competition of Mountain Pine Beetle Fungal Symbionts. MICROBIAL ECOLOGY 2015; 70:336-347. [PMID: 25773718 DOI: 10.1007/s00248-015-0593-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/26/2015] [Indexed: 06/04/2023]
Abstract
The mountain pine beetle, Dendroctonus ponderosae, depends on two fungi, Grosmannia clavigera and Ophiostoma montium, to augment a nutrient-poor woody food resource. Because the two fungi exert differential effects on the host beetle, temperature-driven differences in fungal growth and competition outcomes have a strong potential to influence host population dynamics. Weisolated fungi from beetles and wood from three locations in Montana and Utah, USA, and measured their growth rates and sporulation between 5 and 35 °C on artificial media. We also measured growth rates and percent resource capture for each fungus at 10, 15, 21, and 25 °C during inter- and intra-specific competition. G. clavigera excelled at resource capture at most temperatures. Its optimal growth temperature occurs around 20 °C while that of O. montium occurs near 30 °C. There was no effect of collection site on growth or sporulation; however, O. montium exhibited greater variability in response to temperature than did G. clavigera. Sporulation of G. clavigera was greatest at 30 °C while O. montium sporulated at low levels across all temperatures. During competition experiments, G. clavigera captured more resources than O. montium at most temperatures and captured a greater percentage of resources at a greater rate during inter-specific competition than during intra-specific competition. In contrast, O. montium captured a greater percentage of resources during intra-specific competition. These results demonstrate that temperature can differentially affect growth, sporulation, and resource capture of the two symbionts, indicating that it may be an important factor influencing the composition and dynamics of the symbiosis.
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Affiliation(s)
- Melissa L Moore
- Department of Ecosystem and Conservation Sciences, The University of Montana, Missoula, MT, 59812, USA
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Therrien J, Mason CJ, Cale JA, Adams A, Aukema BH, Currie CR, Raffa KF, Erbilgin N. Bacteria influence mountain pine beetle brood development through interactions with symbiotic and antagonistic fungi: implications for climate-driven host range expansion. Oecologia 2015; 179:467-85. [PMID: 26037523 DOI: 10.1007/s00442-015-3356-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 05/18/2015] [Indexed: 11/30/2022]
Abstract
Bark beetles are associated with diverse communities of symbionts. Although fungi have received significant attention, we know little about how bacteria, and in particular their interactions with fungi, affect bark beetle reproduction. We tested how interactions between four bacterial associates, two symbiotic fungi, and two opportunistic fungi affect performance of mountain pine beetles (Dendroctonus ponderosae) in host tissue. We compared beetle performance in phloem of its historical host, lodgepole pine (Pinus contorta), and its novel host recently accessed through warming climate, jack pine (Pinus banksiana). Overall, beetles produced more larvae, and established longer ovipositional and larval galleries in host tissue predominantly colonized by the symbiotic fungi, Grosmannia clavigera, or Ophiostoma montium than by the opportunistic colonizer Aspergillus and to a lesser extent, Trichoderma. This occurred in both historical and naïve hosts. Impacts of bacteria on beetle reproduction depended on particular fungus-bacterium combinations and host species. Some bacteria, e.g., Pseudomonas sp. D4-22 and Hy4T4 in P. contorta and Pseudomonas sp. Hy4T4 and Stenotrophomonas in P. banksiana, reduced antagonistic effects by Aspergillus and Trichoderma resulting in more larvae and longer ovipositional and larval galleries. These effects were not selective, as bacteria also reduced beneficial effects by symbionts in both host species. Interestingly, Bacillus enhanced antagonistic effects by Aspergillus in both hosts. These results demonstrate that bacteria influence brood development of bark beetles in host tissue. They also suggest that climate-driven range expansion of D. ponderosae through the boreal forest will not be significantly constrained by requirements of, or interactions among, its microbial associates.
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Affiliation(s)
- Janet Therrien
- Department of Renewable Resources, University of Alberta, Edmonton, AB, USA
| | - Charles J Mason
- Department of Entomology, University of Wisconsin, Madison, WI, USA
| | - Jonathan A Cale
- Department of Renewable Resources, University of Alberta, Edmonton, AB, USA
| | - Aaron Adams
- Department of Entomology, University of Wisconsin, Madison, WI, USA
| | - Brian H Aukema
- Department of Entomology, University of Minnesota, St. Paul, MN, USA
| | - Cameron R Currie
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin, Madison, WI, USA
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, AB, USA.
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Silverstein RN, Cunning R, Baker AC. Change in algal symbiont communities after bleaching, not prior heat exposure, increases heat tolerance of reef corals. GLOBAL CHANGE BIOLOGY 2015; 21:236-249. [PMID: 25099991 DOI: 10.1111/gcb.12706] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/13/2014] [Indexed: 05/28/2023]
Abstract
Mutualistic organisms can be particularly susceptible to climate change stress, as their survivorship is often limited by the most vulnerable partner. However, symbiotic plasticity can also help organisms in changing environments by expanding their realized niche space. Coral-algal (Symbiodinium spp.) symbiosis exemplifies this dichotomy: the partnership is highly susceptible to 'bleaching' (stress-induced symbiosis breakdown), but stress-tolerant symbionts can also sometimes mitigate bleaching. Here, we investigate the role of diverse and mutable symbiotic partnerships in increasing corals' ability to thrive in high temperature conditions. We conducted repeat bleaching and recovery experiments on the coral Montastraea cavernosa, and used quantitative PCR and chlorophyll fluorometry to assess the structure and function of Symbiodinium communities within coral hosts. During an initial heat exposure (32 °C for 10 days), corals hosting only stress-sensitive symbionts (Symbiodinium C3) bleached, but recovered (at either 24 °C or 29 °C) with predominantly (>90%) stress-tolerant symbionts (Symbiodinium D1a), which were not detected before bleaching (either due to absence or extreme low abundance). When a second heat stress (also 32 °C for 10 days) was applied 3 months later, corals that previously bleached and were now dominated by D1a Symbiodinium experienced less photodamage and symbiont loss compared to control corals that had not been previously bleached, and were therefore still dominated by Symbiodinium C3. Additional corals that were initially bleached without heat by a herbicide (DCMU, at 24 °C) also recovered predominantly with D1a symbionts, and similarly lost fewer symbionts during subsequent thermal stress. Increased thermotolerance was also not observed in C3-dominated corals that were acclimated for 3 months to warmer temperatures (29 °C) before heat stress. These findings indicate that increased thermotolerance post-bleaching resulted from symbiont community composition changes, not prior heat exposure. Moreover, initially undetectable D1a symbionts became dominant only after bleaching, and were critical to corals' resilience after stress and resistance to future stress.
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Affiliation(s)
- Rachel N Silverstein
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Cswy, Miami, FL, 33149, USA
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Bracewell RR, Six DL. Broadscale specificity in a bark beetle-fungal symbiosis: a spatio-temporal analysis of the mycangial fungi of the western pine beetle. MICROBIAL ECOLOGY 2014; 68:859-870. [PMID: 25004995 DOI: 10.1007/s00248-014-0449-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
Whether and how mutualisms are maintained through ecological and evolutionary time is a seldom studied aspect of bark beetle-fungal symbioses. All bark beetles are associated with fungi and some species have evolved structures for transporting their symbiotic partners. However, the fungal assemblages and specificity in these symbioses are not well known. To determine the distribution of fungi associated with the mycangia of the western pine beetle (Dendroctonus brevicomis), we collected beetles from across the insect's geographic range including multiple genetically distinct populations. Two fungi, Entomocorticium sp. B and Ceratocystiopsis brevicomi, were isolated from the mycangia of beetles from all locations. Repeated sampling at two sites in Montana found that Entomocorticium sp. B was the most prevalent fungus throughout the beetle's flight season, and that females carrying that fungus were on average larger than females carrying C. brevicomi. We present evidence that throughout the flight season, over broad geographic distances, and among genetically distinct populations of beetle, the western pine beetle is associated with the same two species of fungi. In addition, we provide evidence that one fungal species is associated with larger adult beetles and therefore might provide greater benefit during beetle development. The importance and maintenance of this bark beetle-fungus interaction is discussed.
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Affiliation(s)
- Ryan R Bracewell
- Department of Ecosystem and Conservation Sciences, College of Forestry, The University of Montana, 32 Campus Drive, Missoula, MT, 59812, USA,
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38
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Weed AS, Ayres MP, Hicke JA. Consequences of climate change for biotic disturbances in North American forests. ECOL MONOGR 2013. [DOI: 10.1890/13-0160.1] [Citation(s) in RCA: 292] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kolařík M, Jankowiak R. Vector affinity and diversity of Geosmithia fungi living on subcortical insects inhabiting Pinaceae species in central and northeastern Europe. MICROBIAL ECOLOGY 2013; 66:682-700. [PMID: 23624540 DOI: 10.1007/s00248-013-0228-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 04/08/2013] [Indexed: 06/02/2023]
Abstract
Fungi from the genus Geosmithia (Ascomycota: Hypocreales) are associated with bark beetles (Coleoptera: Scolytinae), though little is known about ecology, diversity, and distribution of these fungi across beetle and its host tree species. This study surveyed the diversity, distribution and vector affinity of Geosmithia isolated from subcortical insects that colonized trees from the family Pinaceae in Central and Northeastern Europe. Twelve Geosmithia species were isolated from 85 plant samples associated with 23 subcortical insect species (including 14 bark beetle species). Geosmithia community composition was similar across different localities and vector species; although the fungal communities associated with insects that colonized Pinus differed from that colonizing other tree species (Abies, Larix, and Picea). Ten Geosmithia species from four independent phylogenetic lineages were not reported previously from vectors feeding on other plant families and seem to be restricted to the vectors from Pinaceae only. We conclude that presence of such substrate specificity suggests a long and stable association between Geosmithia and bark beetles.
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Affiliation(s)
- Miroslav Kolařík
- Institute of Microbiology of the ASCR, v. v. i., Vídeňská 1083, 142 20, Prague 4, Czech Republic,
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40
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Hussa EA, Goodrich-Blair H. It Takes a Village: Ecological and Fitness Impacts of Multipartite Mutualism. Annu Rev Microbiol 2013; 67:161-78. [DOI: 10.1146/annurev-micro-092412-155723] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Elizabeth A. Hussa
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706; ,
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706; ,
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Lahr EC, Krokene P. Conifer stored resources and resistance to a fungus associated with the spruce bark beetle Ips typographus. PLoS One 2013; 8:e72405. [PMID: 23967298 PMCID: PMC3742536 DOI: 10.1371/journal.pone.0072405] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 07/10/2013] [Indexed: 11/18/2022] Open
Abstract
Bark beetles and associated fungi are among the greatest natural threats to conifers worldwide. Conifers have potent defenses, but resistance to beetles and fungal pathogens may be reduced if tree stored resources are consumed by fungi rather than used for tree defense. Here, we assessed the relationship between tree stored resources and resistance to Ceratocystis polonica, a phytopathogenic fungus vectored by the spruce bark beetle Ips typographus. We measured phloem and sapwood nitrogen, non-structural carbohydrates (NSC), and lipids before and after trees were attacked by I. typographus (vectoring C. polonica) or artificially inoculated with C. polonica alone. Tree resistance was assessed by measuring phloem lesions and the proportion of necrotic phloem around the tree's circumference following attack or inoculation. While initial resource concentrations were unrelated to tree resistance to C. polonica, over time, phloem NSC and sapwood lipids declined in the trees inoculated with C. polonica. Greater resource declines correlated with less resistant trees (trees with larger lesions or more necrotic phloem), suggesting that resource depletion may be caused by fungal consumption rather than tree resistance. Ips typographus may then benefit indirectly from reduced tree defenses caused by fungal resource uptake. Our research on tree stored resources represents a novel way of understanding bark beetle-fungal-conifer interactions.
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Affiliation(s)
- Eleanor C Lahr
- Division of Biological Sciences, The University of Montana, Missoula, Montana, USA.
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The bark beetle holobiont: why microbes matter. J Chem Ecol 2013; 39:989-1002. [PMID: 23846183 DOI: 10.1007/s10886-013-0318-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/19/2013] [Accepted: 06/27/2013] [Indexed: 01/20/2023]
Abstract
All higher organisms are involved in symbioses with microbes. The importance of these partnerships has led to the concept of the holobiont, defined as the animal or plant with all its associated microbes. Indeed, the interactions between insects and symbionts form much of the basis for the success and diversity of this group of arthropods. Insects rely on microbes to perform basic life functions and to exploit resources and habitats. By "partnering" with microbes, insects access new genomic variation instantaneously allowing the exploitation of new adaptive zones, influencing not only outcomes in ecological time, but the degree of innovation and change that occurs over evolutionary time. In this review, I present a brief overview of the importance of insect-microbe holobionts to illustrate how critical an understanding of the holobiont is to understanding the insect host and it interactions with its environment. I then review what is known about the most influential insect holobionts in many forest ecosystems-bark beetles and their microbes-and how new approaches and technologies are allowing us to illuminate how these symbioses function. Finally, I discuss why it will be critical to study bark beetles as a holobiont to understand the ramifications and extent of anthropogenic change in forest ecosystems.
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Addison AL, Powell JA, Six DL, Moore M, Bentz BJ. The role of temperature variability in stabilizing the mountain pine beetle-fungus mutualism. J Theor Biol 2013; 335:40-50. [PMID: 23791850 DOI: 10.1016/j.jtbi.2013.06.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 06/08/2013] [Accepted: 06/11/2013] [Indexed: 10/26/2022]
Abstract
As global climate patterns continue to change and extreme weather events become increasingly common, it is likely that many ecological interactions will be affected. One such interaction is the multipartite symbiosis that exists between the mountain pine beetle and two species of fungi, Grosmannia clavigera and Ophiostoma montium. In this mutualism, the fungi provide nutrition to the beetle, while the fungi benefit by being dispersed to new host trees. Multi-partite mutualisms are predicted to be unstable due to strong direct competition among symbionts or natural selection for superior over inferior mutualists. However, this mutualism has remained stable over long periods of evolutionary time. In this paper, we developed a temperature-based model for the spread of fungi within a tree and connected it to an existing model for mountain pine beetle development. Using this integrated model for fungal growth, we explored the possibility that temperature variability is a stabilizing mechanism for the mountain pine beetle-fungi mutualism. Of the three types of temperature variability we tested: intra-year, inter-year and variability due to transitioning between different thermal habitats (thermal migration), we found that thermal migration was the most robust stabilizing mechanism. Additionally, we found that the MPB attack density or spacing between fungal lesions also had a significant effect on the stability of the system. High attack densities or close lesion spacings also tended to stabilize the system, regardless of temperature.
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Affiliation(s)
- A L Addison
- Department of Mathematics and Statistics, Utah State University, Logan, UT 84322-3900, USA.
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Hajek AE, Nielsen C, Kepler RM, Long SJ, Castrillo L. Fidelity among Sirex woodwasps and their fungal symbionts. MICROBIAL ECOLOGY 2013; 65:753-62. [PMID: 23532503 PMCID: PMC3622004 DOI: 10.1007/s00248-013-0218-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 03/11/2013] [Indexed: 05/25/2023]
Abstract
We report that associations between mutualistic fungi and their economically and ecologically important woodwasp hosts are not always specific as was previously assumed. Woodwasps in the genus Sirex engage in obligate nutritional ectosymbioses with two species of Amylostereum, a homobasid\iomycete genus of white rot fungi. In the present study, the Amylostereum species and genotypes associated with three species of Sirex native to eastern North America and one relatively recent invasive Sirex from Europe were investigated by comparing intergenic spacer regions (IGS). Sirex spp. were sampled over 6 years from 23 sites in six US states, ranging from Maine in the northeast to Louisiana in the southeast, to obtain samples of Amylostereum from mycangia of adult females. Two of the native Sirex species (Sirex nigricornis and Sirex nitidus) were associated with either Amylostereum chailletii or Amylostereum areolatum, refuting the hypothesis of strict species-specific relationships. However, the invasive Sirex noctilio and the native Sirex cyaneus were each collected with only A. areolatum or A. chailletii, respectively, although S. noctilio was associated with two different IGS genotypes of A. areolatum and S. cyaneus occurs sympatrically with the other native Sirex. In Pinus, the preferred host tree of S. nigricornis and S. noctilio, these species co-occurred in 25.9 % of trees sampled, and horizontal transmission of fungal strains from S. noctilio to S. nigricornis was documented, although only in one tree. The extent that further spread and establishment of S. noctilio will alter the composition of symbionts carried by native Sirex is unknown but will depend in part on the degree of flexibility in these host-symbiont associations.
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Affiliation(s)
- Ann E Hajek
- Department of Entomology, Cornell University, Ithaca, NY 14853-2601, USA.
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Jamieson MA, Trowbridge AM, Raffa KF, Lindroth RL. Consequences of climate warming and altered precipitation patterns for plant-insect and multitrophic interactions. PLANT PHYSIOLOGY 2012; 160:1719-27. [PMID: 23043082 PMCID: PMC3510105 DOI: 10.1104/pp.112.206524] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 10/03/2012] [Indexed: 05/18/2023]
Affiliation(s)
- Mary A Jamieson
- Department of Entomology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Biedermann PHW, Klepzig KD, Taborsky M, Six DL. Abundance and dynamics of filamentous fungi in the complex ambrosia gardens of the primitively eusocial beetle Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae, Scolytinae). FEMS Microbiol Ecol 2012; 83:711-23. [PMID: 23057948 DOI: 10.1111/1574-6941.12026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 09/10/2012] [Accepted: 10/03/2012] [Indexed: 11/26/2022] Open
Abstract
Insect fungus gardens consist of a community of interacting microorganisms that can have either beneficial or detrimental effects to the farmers. In contrast to fungus-farming ants and termites, the fungal communities of ambrosia beetles and the effects of particular fungal species on the farmers are largely unknown. Here, we used a laboratory rearing technique for studying the filamentous fungal garden community of the ambrosia beetle, Xyleborinus saxesenii, which cultivates fungi in tunnels excavated within dead trees. Raffaelea sulfurea and Fusicolla acetilerea were transmitted in spore-carrying organs by gallery founding females and established first in new gardens. Raffaelea sulfurea had positive effects on egg-laying and larval numbers. Over time, four other fungal species emerged in the gardens. Prevalence of one of them, Paecilomyces variotii, correlated negatively with larval numbers and can be harmful to adults by forming biofilms on their bodies. It also comprised the main portion of garden material removed from galleries by adults. Our data suggest that two mutualistic, several commensalistic and one to two pathogenic filamentous fungi are associated with X. saxesenii. Fungal diversity in gardens of ambrosia beetles appears to be much lower than that in gardens of fungus-culturing ants, which seems to result from essential differences in substrates and behaviours.
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Affiliation(s)
- Peter H W Biedermann
- Department of Behavioural Ecology, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.
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Khadempour L, LeMay V, Jack D, Bohlmann J, Breuil C. The relative abundance of mountain pine beetle fungal associates through the beetle life cycle in pine trees. MICROBIAL ECOLOGY 2012; 64:909-917. [PMID: 22735936 DOI: 10.1007/s00248-012-0077-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 05/24/2012] [Indexed: 06/01/2023]
Abstract
The mountain pine beetle (MPB) is a native bark beetle of western North America that attacks pine tree species, particularly lodgepole pine. It is closely associated with the ophiostomatoid ascomycetes Grosmannia clavigera, Leptographium longiclavatum, Ophiostoma montium, and Ceratocystiopsis sp.1, with which it is symbiotically associated. To develop a better understanding of interactions between beetles, fungi, and host trees, we used target-specific DNA primers with qPCR to assess the changes in fungal associate abundance over the stages of the MPB life cycle that occur in galleries under the bark of pine trees. Multivariate analysis of covariance identified statistically significant changes in the relative abundance of the fungi over the life cycle of the MPB. Univariate analysis of covariance identified a statistically significant increase in the abundance of Ceratocystiopsis sp.1 through the beetle life cycle, and pair-wise analysis showed that this increase occurs after the larval stage. In contrast, the abundance of O. montium and Leptographium species (G. clavigera, L. longiclavatum) did not change significantly through the MPB life cycle. From these results, the only fungus showing a significant increase in relative abundance has not been formally described and has been largely ignored by other MPB studies. Although our results were from only one site, in previous studies we have shown that the fungi described were all present in at least ten sites in British Columbia. We suggest that the role of Ceratocystiopsis sp.1 in the MPB system should be explored, particularly its potential as a source of nutrients for teneral adults.
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Silverstein RN, Correa AMS, Baker AC. Specificity is rarely absolute in coral-algal symbiosis: implications for coral response to climate change. Proc Biol Sci 2012; 279:2609-18. [PMID: 22367985 PMCID: PMC3350700 DOI: 10.1098/rspb.2012.0055] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 02/03/2012] [Indexed: 11/12/2022] Open
Abstract
Some reef-building corals have been shown to respond to environmental change by shifting the composition of their algal symbiont (genus Symbiodinium) communities. These shifts have been proposed as a potential mechanism by which corals might survive climate stressors, such as increased temperatures. Conventional molecular methods suggest this adaptive capacity may not be widespread because few (∼25%) coral species have been found to associate with multiple Symbiodinium clades. However, these methods can fail to detect low abundance symbionts (typically less than 10-20% of the total algal symbiont community). To determine whether additional Symbiodinium clades are present, but are not detected using conventional techniques, we applied a high-resolution, real-time PCR assay to survey Symbiodinium (in clades A-D) from 39 species of phylogenetically and geographically diverse scleractinian corals. This survey included 26 coral species thought to be restricted to hosting a single Symbiodinium clade ('symbiotic specialists'). We detected at least two Symbiodinium clades (C and D) in at least one sample of all 39 coral species tested; all four Symbiodinium clades were detected in over half (54%) of the 26 symbiotic specialist coral species. Furthermore, on average, 68 per cent of all sampled colonies within a given coral species hosted two or more symbiont clades. We conclude that the ability to associate with multiple symbiont clades is common in scleractinian (stony) corals, and that, in coral-algal symbiosis, 'specificity' and 'flexibility' are relative terms: specificity is rarely absolute. The potential for reef corals to adapt or acclimatize to environmental change via symbiont community shifts may therefore be more phylogenetically widespread than has previously been assumed.
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Affiliation(s)
- Rachel N Silverstein
- Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149, USA.
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Popa V, Déziel E, Lavallée R, Bauce E, Guertin C. The complex symbiotic relationships of bark beetles with microorganisms: a potential practical approach for biological control in forestry. PEST MANAGEMENT SCIENCE 2012; 68:963-75. [PMID: 22566204 DOI: 10.1002/ps.3307] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 02/10/2012] [Accepted: 02/15/2012] [Indexed: 05/14/2023]
Abstract
Bark beetles, especially Dendroctonus species, are considered to be serious pests of the coniferous forests in North America. Bark beetle forest pests undergo population eruptions, causing region wide economic losses. In order to save forests, finding new and innovative environmentally friendly approaches in wood-boring insect pest management is more important than ever. Several biological control methods have been attempted over time to limit the damage and spreading of bark beetle epidemics. The use of entomopathogenic microorganisms against bark beetle populations is an attractive alternative tool for many biological control programmes in forestry. However, the effectiveness of these biological control agents is strongly affected by environmental factors, as well as by the susceptibility of the insect host. Bark beetle susceptibility to entomopathogens varies greatly between species. According to recent literature, bark beetles are engaged in symbiotic relationships with fungi and bacteria. These types of relationship are very complex and apparently involved in bark beetle defensive mechanisms against pathogens. The latest scientific discoveries in multipartite symbiosis have unravelled unexpected opportunities in bark beetle pest management, which are discussed in this article.
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Affiliation(s)
- Valentin Popa
- INRS-Institut Armand-Frappier, Laval, Quebec, Canada
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Mitton JB, Ferrenberg SM. Mountain Pine Beetle Develops an Unprecedented Summer Generation in Response to Climate Warming. Am Nat 2012; 179:E163-71. [DOI: 10.1086/665007] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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