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Hasik AZ, Bried JT, Bolnick DI, Siepielski AM. Is the local environment more important than within-host interactions in determining coinfection? J Anim Ecol 2024; 93:1541-1555. [PMID: 39245878 DOI: 10.1111/1365-2656.14167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 07/29/2024] [Indexed: 09/10/2024]
Abstract
Host populations often vary in the magnitude of coinfection they experience across environmental gradients. Furthermore, coinfection often occurs sequentially, with a second parasite infecting the host after the first has established a primary infection. Because the local environment and interactions between coinfecting parasites can both drive patterns of coinfection, it is important to disentangle the relative contributions of environmental factors and within-host interactions to patterns of coinfection. Here, we develop a conceptual framework and present an empirical case study to disentangle these facets of coinfection. Across multiple lakes, we surveyed populations of five damselfly (host) species and quantified primary parasitism by aquatic, ectoparasitic water mites and secondary parasitism by terrestrial, endoparasitic gregarines. We first asked if coinfection is predicted by abiotic and biotic factors within the local environment, finding that the probability of coinfection decreased for all host species as pH increased. We then asked if primary infection by aquatic water mites mediated the relationship between pH and secondary infection by terrestrial gregarines. Contrary to our expectations, we found no evidence for a water mite-mediated relationship between pH and gregarines. Instead, the intensity of gregarine infection correlated solely with the local environment, with the magnitude and direction of these relationships varying among environmental predictors. Our findings emphasize the role of the local environment in shaping infection dynamics that set the stage for coinfection. Although we did not detect within-host interactions, the approach herein can be applied to other systems to elucidate the nature of interactions between hosts and coinfecting parasites within complex ecological communities.
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Affiliation(s)
- Adam Z Hasik
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Beersheva, Midreshet Ben-Gurion, Israel
| | - Jason T Bried
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
| | - Daniel I Bolnick
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Adam M Siepielski
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, USA
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2
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Tiritelli R, Giannetti D, Schifani E, Grasso DA, Cilia G. Neighbors sharing pathogens: the intricate relationship between Apis mellifera and ants (Hymenoptera: Formicidae) nesting in hives. INSECT SCIENCE 2024. [PMID: 39126179 DOI: 10.1111/1744-7917.13433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/29/2024] [Accepted: 07/16/2024] [Indexed: 08/12/2024]
Abstract
Ants are ubiquitous and eusocial insects that exhibit frequent physical contact among colony members, thereby increasing their susceptibility to diseases. Some species are often found in beehives and in their surroundings, where they exploit the food resources of honey bees. This intricate relationship may facilitate the interspecific transmission of honey bee pathogens to ants, although ants themselves may contribute to spillback phenomena. The objective of this study was to assess the presence and abundance of honey bee pathogens in ants sampled from Italian apiaries. A total of 37 colonies within 24 apiaries across 7 regions were monitored. In total, 6 pathogens were detected in adult ants and 3 in the brood. In particular, the study revealed a high prevalence of honey bee pathogens in ants, with DWV, BQCV, and CBPV being the most commonly encountered. The brood also tested positive for the same viruses. Notably, all analyzed viruses were found to be replicative in both adult ants and ant broods. Furthermore, co-infections were prevalent, suggesting complex pathogen interactions within ant populations. Statistical analysis indicated significant differences in pathogen prevalence and abundance among ant species and sample types. The findings highlight active infection in both the ants and the brood, suggesting a potential role of ants as reservoir hosts and vectors of honey bee pathogens emphasizing the need for further research to understand the implications of interspecific pathogen transmission on ant and bee health.
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Affiliation(s)
- Rossella Tiritelli
- CREA Research Centre for Agriculture and Environment (CREA-AA), Bologna, Italy
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parma, Italy
| | - Daniele Giannetti
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parma, Italy
| | - Enrico Schifani
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parma, Italy
| | - Donato A Grasso
- Department of Chemistry, Life Sciences & Environmental Sustainability, University of Parma, Parma, Italy
| | - Giovanni Cilia
- CREA Research Centre for Agriculture and Environment (CREA-AA), Bologna, Italy
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Habig M, Grasse AV, Müller J, Stukenbrock EH, Leitner H, Cremer S. Frequent horizontal chromosome transfer between asexual fungal insect pathogens. Proc Natl Acad Sci U S A 2024; 121:e2316284121. [PMID: 38442176 PMCID: PMC10945790 DOI: 10.1073/pnas.2316284121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/24/2024] [Indexed: 03/07/2024] Open
Abstract
Entire chromosomes are typically only transmitted vertically from one generation to the next. The horizontal transfer of such chromosomes has long been considered improbable, yet gained recent support in several pathogenic fungi where it may affect the fitness or host specificity. To date, it is unknown how these transfers occur, how common they are, and whether they can occur between different species. In this study, we show multiple independent instances of horizontal transfers of the same accessory chromosome between two distinct strains of the asexual entomopathogenic fungus Metarhizium robertsii during experimental co-infection of its insect host, the Argentine ant. Notably, only the one chromosome-but no other-was transferred from the donor to the recipient strain. The recipient strain, now harboring the accessory chromosome, exhibited a competitive advantage under certain host conditions. By phylogenetic analysis, we further demonstrate that the same accessory chromosome was horizontally transferred in a natural environment between M. robertsii and another congeneric insect pathogen, Metarhizium guizhouense. Hence, horizontal chromosome transfer is not limited to the observed frequent events within species during experimental infections but also occurs naturally across species. The accessory chromosome that was transferred contains genes that may be involved in its preferential horizontal transfer or support its establishment. These genes encode putative histones and histone-modifying enzymes, as well as putative virulence factors. Our study reveals that both intra- and interspecies horizontal transfer of entire chromosomes is more frequent than previously assumed, likely representing a not uncommon mechanism for gene exchange.
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Affiliation(s)
- Michael Habig
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Anna V. Grasse
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
| | - Judith Müller
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University of Kiel, Kiel24118, Germany
- Max Planck Institute for Evolutionary Biology, Plön24306, Germany
| | - Hanna Leitner
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
| | - Sylvia Cremer
- Institute of Science and Technology Austria (ISTA), Klosterneuburg3400, Austria
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Stock M, Milutinović B, Hoenigsberger M, Grasse AV, Wiesenhofer F, Kampleitner N, Narasimhan M, Schmitt T, Cremer S. Pathogen evasion of social immunity. Nat Ecol Evol 2023; 7:450-460. [PMID: 36732670 PMCID: PMC9998270 DOI: 10.1038/s41559-023-01981-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 01/04/2023] [Indexed: 02/04/2023]
Abstract
Treating sick group members is a hallmark of collective disease defence in vertebrates and invertebrates alike. Despite substantial effects on pathogen fitness and epidemiology, it is still largely unknown how pathogens react to the selection pressure imposed by care intervention. Using social insects and pathogenic fungi, we here performed a serial passage experiment in the presence or absence of colony members, which provide social immunity by grooming off infectious spores from exposed individuals. We found specific effects on pathogen diversity, virulence and transmission. Under selection of social immunity, pathogens invested into higher spore production, but spores were less virulent. Notably, they also elicited a lower grooming response in colony members, compared with spores from the individual host selection lines. Chemical spore analysis suggested that the spores from social selection lines escaped the caregivers' detection by containing lower levels of ergosterol, a key fungal membrane component. Experimental application of chemically pure ergosterol indeed induced sanitary grooming, supporting its role as a microbe-associated cue triggering host social immunity against fungal pathogens. By reducing this detection cue, pathogens were able to evade the otherwise very effective collective disease defences of their social hosts.
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Affiliation(s)
- Miriam Stock
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria
| | - Barbara Milutinović
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria. .,Laboratory of Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.
| | | | - Anna V Grasse
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria
| | | | - Niklas Kampleitner
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria
| | | | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, University of Würzburg, Würzburg, Germany
| | - Sylvia Cremer
- ISTA (Institute of Science and Technology Austria), Klosterneuburg, Austria.
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Armitage SAO, Milutinović B. Editorial overview: Evolutionary ecology of insect immunity. CURRENT OPINION IN INSECT SCIENCE 2022; 53:100948. [PMID: 35777617 DOI: 10.1016/j.cois.2022.100948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Affiliation(s)
- Sophie A O Armitage
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Straße 1-3, 14195 Berlin, Germany.
| | - Barbara Milutinović
- Laboratory of Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia
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Lutermann H. Socializing in an Infectious World: The Role of Parasites in Social Evolution of a Unique Rodent Family. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.879031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Transmission of parasites between hosts is facilitated by close contact of hosts. Consequently, parasites have been proposed as an important constraint to the evolution of sociality accounting for its rarity. Despite the presumed costs associated with parasitism, the majority of species of African mole-rats (Family: Bathyergidae) are social. In fact, only the extremes of sociality (i.e., solitary and singular breeding) are represented in this subterranean rodent family. But how did bathyergids overcome the costs of parasitism? Parasite burden is a function of the exposure and susceptibility of a host to parasites. In this review I explore how living in sealed burrow systems and the group defenses that can be employed by closely related group members can effectively reduce the exposure and susceptibility of social bathyergids to parasites. Evidence suggests that this can be achieved largely by investment in relatively cheap and flexible behavioral rather than physiological defense mechanisms. This also shifts the selection pressure for parasites on successful transmission between group members rather than transmission between groups. In turn, this constrains the evolution of virulence and favors socially transmitted parasites (e.g., mites and lice) further reducing the costs of parasitism for social Bathyergidae. I conclude by highlighting directions for future research to evaluate the mechanisms proposed and to consider parasites as facilitators of social evolution not only in this rodent family but also other singular breeders.
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Milutinović B, Schmitt T. Chemical cues in disease recognition and their immunomodulatory role in insects. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100884. [PMID: 35151903 DOI: 10.1016/j.cois.2022.100884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Preventing infections is crucial for host fitness and many insects modify their behaviour upon sensing a contagion. We review chemical cues that mediate insect behaviour in response to parasites, and diseased or dead conspecifics. Considering the large diversity of behavioural disease defences described, surprisingly little is known about disease-associated cues that mediate them, especially their chemoreceptor and neuronal details. Interestingly, disease cues do not only modify host behaviour, but they could also play a direct role in immune system activation via neuroendocrine regulation, bypassing the need for risky immunological contact with the parasite. Such crosstalk is an exciting emerging research area in insect ecological immunology that should prove invaluable in studying host-parasite interactions by combining analytical methods from chemical ecology.
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Affiliation(s)
- Barbara Milutinović
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstrasse 1, 48149 Münster, Germany; Laboratory of Evolutionary Genetics, Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.
| | - Thomas Schmitt
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
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Empirical Support for the Pattern of Competitive Exclusion between Insect Parasitic Fungi. J Fungi (Basel) 2021; 7:jof7050385. [PMID: 34069271 PMCID: PMC8157078 DOI: 10.3390/jof7050385] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 02/06/2023] Open
Abstract
Fungal entomopathogens are largely facultative parasites and play an important role in controlling the density of insect populations in nature. A few species of these fungi have been used for biocontrol of insect pests. The pattern of the entomopathogen competition for insect individuals is still elusive. Here, we report the empirical competition for hosts or niches between the inter- and intra-species of the entomopathogens Metarhizium robertsii and Beauveria bassiana. It was found that the synergistic effect of coinfection on virulence increase was not evident, and the insects were largely killed and mycosed by M. robertsii independent of its initial co-inoculation dosage and infection order. For example, >90% dead insects were mycosed by M. robertsii even after immersion in a spore suspension with a mixture ratio of 9:1 for B. bassiana versus M. robertsii. The results thus support the pattern of competitive exclusion between insect pathogenic fungi that occurred from outside to inside the insect hosts. Even being inferior to compete for insects, B. bassiana could outcompete M. robertsii during co-culturing in liquid medium. It was also found that the one-sided mycosis of insects occurred during coinfection with different genotypic strains of either fungi. However, parasexual recombination was evident to take place between the compatible strains after coinfection. The data of this study can help explain the phenomena of the exclusive mycosis of insect individuals, but co-occurrence of entomopathogens in the fields, and suggest that the synergistic effect is questionable regarding the mixed use of fungal parasites for insect pest control.
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9
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Pull CD, McMahon DP. Superorganism Immunity: A Major Transition in Immune System Evolution. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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