scholarly journals The Evolution of Host Specialization in an Insect Pathogen

2021 ◽  
Author(s):  
Elisa Visher ◽  
Lawrence Uricchio ◽  
Lewis Bartlett ◽  
Nicole DeNamur ◽  
Aren Yarcan ◽  
...  

AbstractNiche breadth coevolution between biotic partners underpins theories of diversity and co-existence and influences patterns of disease emergence and transmission in host-parasite systems. Despite these broad implications, we still do not fully understand how the breadth of parasites’ infectivity evolves, the nature of any associated costs, or the genetic basis of specialization. Here, we serially passage a granulosis virus on multiple inbred populations of its Plodia interpunctella host to explore the dynamics and outcomes of specialization. In particular, we collect time series of phenotypic and genetic data to explore the dynamics of host genotype specialization throughout the course of experimental evolution and examine two fitness components. We find that the Plodia interpunctella granulosis virus consistently evolves increases in overall specialization, but that our two fitness components evolve independently such that lines specialize in either productivity or infectivity. Furthermore, we find that specialization in our experiment is a highly polygenic trait best explained by a combination of evolutionary mechanisms including conditionally positive fitness asymmetries and mutation accumulation. These results are important for understanding the evolution of specialization in host-parasite interactions and its broader implications for co-existence, diversification, and infectious disease management.

2019 ◽  
Author(s):  
Daniel Padfield ◽  
Meaghan Castledine ◽  
Angus Buckling

AbstractThermal performance curves (TPCs) are used to predict changes in species interactions, and hence range shifts, disease dynamics and community composition, under forecasted climate change. Species interactions might in turn affect TPCs. Here, we investigate whether temperature-dependent changes in a microbial host-parasite interaction (the bacterium Pseudomonas fluorescens, and its bacteriophage, SBWФ2) changes the host TPC. The bacteriophage had a narrower infectivity range, with their critical thermal maximum ∼6°C lower than those at which the bacteria still had high growth. Consequently, in the presence of phage, the host TPC had a higher optimum temperature and a lower maximum growth rate. These changes were driven by a temperature-dependent evolution, and cost, of resistance; the largest cost of resistance occurring where bacteria grew best in the absence of phage. Our work highlights how ecological and evolutionary mechanisms can alter the effect of a parasite on host thermal performance, even over very short timescales.Data accessibility statementAll data and R code used in the analysis will be made available on GitHub and archived on Zenodo.


2010 ◽  
Vol 7 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Corine N. Schoebel ◽  
Christoph Tellenbach ◽  
Piet Spaak ◽  
Justyna Wolinska

Both host susceptibility and parasite infectivity commonly have a genetic basis, and can therefore be shaped by coevolution. However, these traits are often sensitive to environmental variation, resulting in genotype-by-environment interactions. We tested the influence of temperature on host–parasite genetic specificity in the Daphnia longispina hybrid complex, exposed to the protozoan parasite Caullerya mesnili . Infection rates were higher at low temperature. Furthermore, significant differences between host clones, but not between host taxa, and a host genotype-by-temperature interaction were observed.


Parasitology ◽  
2013 ◽  
Vol 140 (5) ◽  
pp. 587-597 ◽  
Author(s):  
J. KOPRIVNIKAR ◽  
H. S. RANDHAWA

SUMMARYThe range of hosts used by a parasite is influenced by macro-evolutionary processes (host switching, host–parasite co-evolution), as well as ‘encounter filters’ and ‘compatibility filters’ at the micro-evolutionary level driven by host/parasite ecology and physiology. Host specialization is hypothesized to result in trade-offs with aspects of parasite life history (e.g. reproductive output), but these have not been well studied. We used previously published data to create models examining general relationships among host specificity and important aspects of life history and reproduction for nematodes parasitizing animals. Our results indicate no general trade-off between host specificity and the average pre-patent period (time to first reproduction), female size, egg size, or fecundity of these nematodes. However, female size was positively related to egg size, fecundity, and pre-patent period. Host compatibility may thus not be the primary determinant of specificity in these parasitic nematodes if there are few apparent trade-offs with reproduction, but rather, the encounter opportunities for new host species at the micro-evolutionary level, and other processes at the macro-evolutionary level (i.e. phylogeny). Because host specificity is recognized as a key factor determining the spread of parasitic diseases understanding factors limiting host use are essential to predict future changes in parasite range and occurrence.


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