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Zilio G, Nørgaard LS, Gougat-Barbera C, Hall MD, Fronhofer EA, Kaltz O. Travelling with a parasite: the evolution of resistance and dispersal syndromes during experimental range expansion. Proc Biol Sci 2023; 290:20221966. [PMID: 36598014 PMCID: PMC9811632 DOI: 10.1098/rspb.2022.1966] [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: 09/30/2022] [Accepted: 11/29/2022] [Indexed: 01/05/2023] Open
Abstract
Rapid evolutionary change during range expansions can lead to diverging range core and front populations, with the emergence of dispersal syndromes (coupled responses in dispersal and life-history traits). Besides intraspecific effects, range expansions may be impacted by interspecific interactions such as parasitism. Yet, despite the potentially large impact of parasites imposing additional selective pressures on the host, their role on range expansions remains largely unexplored. Using microcosm populations of the ciliate Paramecium caudatum and its bacterial parasite Holospora undulata, we studied experimental range expansions under parasite presence or absence. We found that the interaction of range expansion and parasite treatments affected the evolution of host dispersal syndromes. Namely, front populations showed different associations of population growth parameters and swimming behaviours than core populations, indicating divergent evolution. Parasitism reshaped trait associations, with hosts evolved in the presence of the parasite exhibiting overall increased resistance and reduced dispersal. Nonetheless, when comparing infected range core and front populations, we found a positive association, suggesting joint evolution of resistance and dispersal at the front. We conclude that host-parasite interactions during range expansions can change evolutionary trajectories; this in turn may feedback on the ecological dynamics of the range expansion and parasite epidemics.
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Affiliation(s)
- Giacomo Zilio
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier 34000, France
| | - Louise S. Nørgaard
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne 3800, Australia
| | | | - Matthew D. Hall
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Melbourne 3800, Australia
| | | | - Oliver Kaltz
- ISEM, University of Montpellier, CNRS, EPHE, IRD, Montpellier 34000, France
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Flemming FE, Grosser K, Schrallhammer M. Natural Shifts in Endosymbionts' Occurrence and Relative Frequency in Their Ciliate Host Population. Front Microbiol 2022; 12:791615. [PMID: 35087493 PMCID: PMC8787144 DOI: 10.3389/fmicb.2021.791615] [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: 10/08/2021] [Accepted: 12/14/2021] [Indexed: 11/13/2022] Open
Abstract
The role of bacterial endosymbionts harbored by heterotrophic Paramecium species is complex. Obligate intracellular bacteria supposedly always inflict costs as the host is the only possible provider of resources. However, several experimental studies have shown that paramecia carrying bacterial endosymbionts can benefit from their infection. Here, we address the question which endosymbionts occur in natural paramecia populations isolated from a small lake over a period of 5 years and which factors might explain observed shifts and persistence in the symbionts occurrence. One hundred and nineteen monoclonal strains were investigated and approximately two-third harbored intracellular bacteria. The majority of infected paramecia carried the obligate endosymbiotic "Candidatus Megaira polyxenophila", followed by Caedimonas varicaedens, and Holospora undulata. The latter was only detected in a single strain. While "Ca. M. polyxenophila" was observed in seven out of 13 samplings, C. varicaedens presence was limited to a single sampling occasion. After the appearance of C. varicaedens, "Ca. M. polyxenophila" prevalence dramatically dropped with some delay but recovered to original levels at the end of our study. Potential mechanisms explaining these observations include differences in infectivity, host range, and impact on host fitness as well as host competitive capacities. Growth experiments revealed fitness advantages for infected paramecia harboring "Ca. M. polyxenophila" as well as C. varicaedens. Furthermore, we showed that cells carrying C. varicaedens gain a competitive advantage from the symbiosis-derived killer trait. Other characteristics like infectivity and overlapping host range were taken into consideration, but the observed temporal persistence of "Ca. M. polyxenophila" is most likely explained by the positive effect this symbiont provides to its host.
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Affiliation(s)
- Felicitas E. Flemming
- Microbiology, Institute of Biology II, Albert Ludwig University of Freiburg, Freiburg, Germany
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Zilio G, Nørgaard LS, Petrucci G, Zeballos N, Gougat-Barbera C, Fronhofer EA, Kaltz O. Parasitism and host dispersal plasticity in an aquatic model system. J Evol Biol 2021; 34:1316-1325. [PMID: 34157176 DOI: 10.1111/jeb.13893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/19/2021] [Accepted: 06/16/2021] [Indexed: 11/28/2022]
Abstract
Dispersal is a central determinant of spatial dynamics in communities and ecosystems, and various ecological factors can shape the evolution of constitutive and plastic dispersal behaviours. One important driver of dispersal plasticity is the biotic environment. Parasites, for example, influence the internal condition of infected hosts and define external patch quality. Thus, state-dependent dispersal may be determined by infection status and context-dependent dispersal by the abundance of infected hosts in the population. A prerequisite for such dispersal plasticity to evolve is a genetic basis on which natural selection can act. Using interconnected microcosms, we investigated dispersal in experimental populations of the freshwater protist Paramecium caudatum in response to the bacterial parasite Holospora undulata. For a collection of 20 natural host strains, we found substantial variation in constitutive dispersal and to a lesser degree in dispersal plasticity. First, infection tended to increase or decrease dispersal relative to uninfected controls, depending on strain identity, indicative of state-dependent dispersal plasticity. Infection additionally decreased host swimming speed compared to the uninfected counterparts. Second, for certain strains, there was a weak negative association between dispersal and infection prevalence, such that uninfected hosts dispersed less when infection was more frequent in the population, indicating context-dependent dispersal plasticity. Future experiments may test whether the observed differences in dispersal plasticity are sufficiently strong to be picked up by natural selection. The evolution of dispersal plasticity as a strategy to mitigate parasite effects spatially may have important implications for epidemiological dynamics.
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Affiliation(s)
- Giacomo Zilio
- ISEM, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France
| | - Louise S Nørgaard
- ISEM, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France.,School of Biological Sciences, Monash University, Melbourne, Vic., Australia
| | - Giovanni Petrucci
- ISEM, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France
| | - Nathalie Zeballos
- ISEM, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France.,CEFE, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France
| | | | | | - Oliver Kaltz
- ISEM, CNRS, EPHE, IRD, University of Montpellier, Montpellier, France
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Nørgaard LS, Zilio G, Saade C, Gougat‐Barbera C, Hall MD, Fronhofer EA, Kaltz O. An evolutionary trade‐off between parasite virulence and dispersal at experimental invasion fronts. Ecol Lett 2021; 24:739-750. [DOI: 10.1111/ele.13692] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/30/2020] [Accepted: 12/23/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Louise S. Nørgaard
- School of Biological Sciences Centre for Geometric Biology Monash University Melbourne3800Australia
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | - Giacomo Zilio
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | - Camille Saade
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
| | | | - Matthew D. Hall
- School of Biological Sciences Centre for Geometric Biology Monash University Melbourne3800Australia
| | | | - Oliver Kaltz
- ISEMUniversity of MontpellierCNRSIRDEPHE Montpellier France
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