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Experimental evolution of infectious behaviour in a facultative ectoparasite
Author(s) -
Durkin E. S.,
Luong L. T.
Publication year - 2018
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.13227
Subject(s) - biology , facultative , parasitism , obligate , evolutionary biology , heritability , genetic variation , selection (genetic algorithm) , natural selection , mite , zoology , experimental evolution , human evolutionary genetics , trait , obligate parasite , genetics , host (biology) , ecology , phylogenetics , gene , artificial intelligence , computer science , programming language
Parasitic lifestyles have evolved many times in animals, but how such life‐history strategies evolved from free‐living ancestors remains a great puzzle. Transitional symbiotic strategies, such as facultative parasitism, are hypothesized evolutionary stepping stones towards obligate parasitism. However, to consider this hypothesis, heritable genetic variation in infectious behaviour of transitional symbiotic strategies must exist. In this study, we experimentally evolved infectivity and estimated the additive genetic variation in a facultative parasite. We performed artificial selection experiments in which we selected for either increased or decreased propensity to infect in a facultatively parasitic mite ( Macrocheles muscaedomesticae ). Here, infectiousness was expressed in terms of mite attachment to a host ( Drosophila hydei ) and modelled as a threshold trait. Mites responded positively to selection for increased infectivity; realized heritability of infectious behaviour was significantly different from zero and estimated to be 16.6% (±4.4% SE ). Further, infection prevalence was monitored for 20 generations post‐selection. Selected lines continued to display relatively high levels of infection, demonstrating a degree of genetic stability in infectiousness. Our study is the first to provide an estimate of heritability and additive genetic variation for infectious behaviour in a facultative parasite, which suggests natural selection can act upon facultative strategies with important implications for the evolution of parasitism.