Ecological Context Influences Evolution in Host-Parasite Interactions: Insights from the Daphnia-Parasite Model System*

McLean, Katherine D.; Duffy, Meghan A.

doi:10.1007/978-3-030-39831-6_21

Cited by 4 publications

(6 citation statements)

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“…Another system that has been used to understand evolution in host-parasite interactions is the Daphnia (zooplankton host)- Pasteuria ramosa (bacterial parasite) system (Ebert 2008 ; Ebert et al 2016 ; Wale and Duffy 2021 ). One advantage of this system is that it allows for studies that bridge between the field and the lab (McLean and Duffy 2020 ); another is that hosts and parasites both produce long-lived resting stages that are incorporated into sediments (Decaestecker et al 2004 ). A study that took advantage of this latter feature found that P. ramosa evolved differences in its within-host growth rate and effects on fecundity (Decaestecker et al 2007 ); because that study used hosts and parasites from sediment cores, it looked at longer term dynamics of host-parasite coevolution over a span of several decades and combined hosts and parasites produced over multiple years.…”

Section: Introductionmentioning

confidence: 99%

Virulence evolution during a naturally occurring parasite outbreak

et al. 2022

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Virulence, the degree to which a pathogen harms its host, is an important but poorly understood aspect of host-pathogen interactions. Virulence is not static, instead depending on ecological context and potentially evolving rapidly. For instance, at the start of an epidemic, when susceptible hosts are plentiful, pathogens may evolve increased virulence if this maximizes their intrinsic growth rate. However, if host density declines during an epidemic, theory predicts evolution of reduced virulence. Although well-studied theoretically, there is still little empirical evidence for virulence evolution in epidemics, especially in natural settings with native host and pathogen species. Here, we used a combination of field observations and lab assays in the Daphnia-Pasteuria model system to look for evidence of virulence evolution in nature. We monitored a large, naturally occurring outbreak of Pasteuria ramosa in Daphnia dentifera, where infection prevalence peaked at ~ 40% of the population infected and host density declined precipitously during the outbreak. In controlled infections in the lab, lifespan and reproduction of infected hosts was lower than that of unexposed control hosts and of hosts that were exposed but not infected. We did not detect any significant changes in host resistance or parasite infectivity, nor did we find evidence for shifts in parasite virulence (quantified by host lifespan and number of clutches produced by hosts). However, over the epidemic, the parasite evolved to produce significantly fewer spores in infected hosts. While this finding was unexpected, it might reflect previously quantified tradeoffs: parasites in high mortality (e.g., high predation) environments shift from vegetative growth to spore production sooner in infections, reducing spore yield. Future studies that track evolution of parasite spore yield in more populations, and that link those changes with genetic changes and with predation rates, will yield better insight into the drivers of parasite evolution in the wild.

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Section: Introductionmentioning

confidence: 99%

Virulence evolution during a naturally occurring parasite outbreak

et al. 2022

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“…Experimental model systems have been essential for testing hypotheses about infectious disease biology [21][22][23]. Indeed, major discoveries in immunity, pathogenesis, and pathogen ecology and evolution come from model systems such as Mus musculus [24], Drosophila melanogaster [25], Daphnia species [21], Arabadopsis thaliana [26] and Caenorhabditis elegans [27]. However, few model systems exist to study the ecology and evolution of disease spillover and emergence, and the systems that do exist lack key features known to drive disease dynamics (e.g.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Developing an empirical model for spillover and emergence: Orsay virus host range inCaenorhabditis

Shaw

Kennedy

2022

Proc. R. Soc. B.

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A lack of tractable experimental systems in which to test hypotheses about the ecological and evolutionary drivers of disease spillover and emergence has limited our understanding of these processes. Here we introduce a promising system: Caenorhabditis hosts and Orsay virus, a positive-sense single-stranded RNA virus that naturally infects C. elegans . We assayed species across the Caenorhabditis tree and found Orsay virus susceptibility in 21 of 84 wild strains belonging to 14 of 44 species. Confirming patterns documented in other systems, we detected effects of host phylogeny on susceptibility. We then tested whether susceptible strains were capable of transmitting Orsay virus by transplanting exposed hosts and determining whether they transmitted infection to conspecifics during serial passage. We found no evidence of transmission in 10 strains (virus undetectable after passaging in all replicates), evidence of low-level transmission in 5 strains (virus lost between passage 1 and 5 in at least one replicate) and evidence of sustained transmission in 6 strains (including all three experimental C. elegans strains) in at least one replicate. Transmission was strongly associated with viral amplification in exposed populations. Variation in Orsay virus susceptibility and transmission among Caenorhabditis strains suggests that the system could be powerful for studying spillover and emergence.

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Section: Introductionmentioning

confidence: 99%

“…Daphnia species [21], Arabadopsis thaliana [26], and Caenorhabditis elegans [27]. These systems have important traits that make them amenable to experimentation: they are inexpensive, have fast generation times, and have simplified genetics since they are usually hermaphroditic, asexual, or inbred.…”

Section: Introductionmentioning

confidence: 99%

Developing an empirical model for spillover and emergence: Orsay virus host range in Caenorhabditis

Shaw

Kennedy

2021

Preprint

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A lack of tractable experimental systems in which to test hypotheses about the ecological and evolutionary drivers of disease spillover and emergence has limited our understanding of these processes. Here we introduce a promising system: Caenorhabditis hosts and Orsay virus, a positive-sense single-stranded RNA virus that naturally infects C. elegans. We assayed the susceptibility of species across the Caenorhabditis tree and found 21 of 84 wild strains belonging to 14 of 44 species to be susceptible to Orsay virus. Confirming patterns documented in other systems, we detected effects of host phylogeny on susceptibility. We then tested whether susceptible strains were capable of transmitting Orsay virus by transplanting exposed hosts and determining whether they transmitted infection to conspecifics during serial passage. We found no evidence of transmission in 10 strains (virus undetectable after passaging), evidence of low-level transmission in 5 strains (virus lost between passage 1 and 5), and evidence of sustained transmission in 6 strains (including all 3 experimental C. elegans strains). Transmission was associated with host phylogeny and with viral amplification in exposed populations. Variation in Orsay virus susceptibility and transmission among Caenorhabditis species suggests that the system could be powerful for studying spillover and emergence.

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Ecological Context Influences Evolution in Host-Parasite Interactions: Insights from the Daphnia-Parasite Model System*

Cited by 4 publications

References 0 publications

Virulence evolution during a naturally occurring parasite outbreak

Virulence evolution during a naturally occurring parasite outbreak

Developing an empirical model for spillover and emergence: Orsay virus host range inCaenorhabditis

Developing an empirical model for spillover and emergence: Orsay virus host range in Caenorhabditis

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