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Understanding Host-Switching by Ecological Fitting.

Araujo SB, Braga MP, Brooks DR, Agosta SJ, Hoberg EP, von Hartenthal FW, Boeger WA - PLoS ONE (2015)

Bottom Line: The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later.The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes.Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Ecologia Molecular e Parasitologia Evolutiva, Universidade Federal do Paraná, Caixa Postal 19073, Curitiba, PR 81531-980, Brazil; Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, PR 81531-980, Brazil.

ABSTRACT
Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.

No MeSH data available.


Flowchart of the model.In each generation, every parasite has a chance to reproduce, disperse to a new host, and die due to the selection pressure imposed by its respective host. For simplicity, after each case of successful host-switch, the parasite population on the ancestral host is no longer modeled and the “new host” becomes the “original host”. The simulation stops when all individuals die.
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pone.0139225.g001: Flowchart of the model.In each generation, every parasite has a chance to reproduce, disperse to a new host, and die due to the selection pressure imposed by its respective host. For simplicity, after each case of successful host-switch, the parasite population on the ancestral host is no longer modeled and the “new host” becomes the “original host”. The simulation stops when all individuals die.

Mentions: We evaluate the extent of host switching of a parasite lineage under variable Fitness Space using an Individual Based Model (parasite individuals are explicitly modeled). Each parasite expresses a phenotype that is defined by a value of relative fitness to a host resource. The model dynamics emerge by offering different hosts to the parasites and imposing reproduction, dispersion and mortality events (Fig 1). A program was designed to run the simulations (versions executable in Windows, Linux, and MacIntosh are available at http://fisica.ufpr.br/araujosbl).


Understanding Host-Switching by Ecological Fitting.

Araujo SB, Braga MP, Brooks DR, Agosta SJ, Hoberg EP, von Hartenthal FW, Boeger WA - PLoS ONE (2015)

Flowchart of the model.In each generation, every parasite has a chance to reproduce, disperse to a new host, and die due to the selection pressure imposed by its respective host. For simplicity, after each case of successful host-switch, the parasite population on the ancestral host is no longer modeled and the “new host” becomes the “original host”. The simulation stops when all individuals die.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592216&req=5

pone.0139225.g001: Flowchart of the model.In each generation, every parasite has a chance to reproduce, disperse to a new host, and die due to the selection pressure imposed by its respective host. For simplicity, after each case of successful host-switch, the parasite population on the ancestral host is no longer modeled and the “new host” becomes the “original host”. The simulation stops when all individuals die.
Mentions: We evaluate the extent of host switching of a parasite lineage under variable Fitness Space using an Individual Based Model (parasite individuals are explicitly modeled). Each parasite expresses a phenotype that is defined by a value of relative fitness to a host resource. The model dynamics emerge by offering different hosts to the parasites and imposing reproduction, dispersion and mortality events (Fig 1). A program was designed to run the simulations (versions executable in Windows, Linux, and MacIntosh are available at http://fisica.ufpr.br/araujosbl).

Bottom Line: The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later.The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes.Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Ecologia Molecular e Parasitologia Evolutiva, Universidade Federal do Paraná, Caixa Postal 19073, Curitiba, PR 81531-980, Brazil; Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba, PR 81531-980, Brazil.

ABSTRACT
Despite the fact that parasites are highly specialized with respect to their hosts, empirical evidence demonstrates that host switching rather than co-speciation is the dominant factor influencing the diversification of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing ecological specialists to host-switch readily. That proposal is tested herein using an individual-based model of host switching. The model considers a parasite species exposed to multiple host resources. Through time host range expansion can occur readily without the prior evolution of novel genetic capacities. It also produces non-linear variation in the size of the fitness space. The capacity for host colonization is strongly influenced by propagule pressure early in the process and by the size of the fitness space later. The simulations suggest that co-adaptation may be initiated by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and thus may colonize distantly related hosts by a "stepping-stone" process.

No MeSH data available.