Evolution of drug-tolerant nematode populations in response to density reduction

Reynolds, A., Lindstrom, J. , Johnson, P. C.D. and Mable, B. K. (2016) Evolution of drug-tolerant nematode populations in response to density reduction. Evolutionary Applications, 9(5), pp. 726-738. (doi: 10.1111/eva.12376) (PMID:27247622) (PMCID:PMC4869413)

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Resistance to xenobiotics remains a pressing issue in parasite treatment and global agriculture. Multiple factors may affect the evolution of resistance, including interactions between life-history traits and the strength of selection imposed by different drug doses. We experimentally created replicate selection lines of free-living Caenorhabditis remanei exposed to Ivermectin at high and low doses to assess whether survivorship of lines selected in drug-treated environments increased, and if this varied with dose. Additionally, we maintained lines where mortality was imposed randomly to control for differences in density between drug treatments and to distinguish between the evolutionary consequences of drug-treatment versus ecological processes due to changes in density-dependent feedback. After 10 generations, we exposed all of the selected lines to high-dose, low-dose and drug-free environments to evaluate evolutionary changes in survivorship as well as any costs to adaptation. Both adult and juvenile survival were measured to explore relationships between life-history stage, selection regime and survival. Intriguingly, both drug-selected and random-mortality lines showed an increase in survivorship when challenged with Ivermectin; the magnitude of this increase varied with the intensity of selection and life-history stage. Our results suggest that interactions between density-dependent processes and life history may mediate evolved changes in susceptibility to control measures.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Lindstrom, Dr Jan and Johnson, Dr Paul and Mable, Professor Barbara
Authors: Reynolds, A., Lindstrom, J., Johnson, P. C.D., and Mable, B. K.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Evolutionary Applications
ISSN (Online):1752-4571
Published Online:29 March 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Evolutionary Applications 9(5):726-738)
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
586271NERC DTG 2011-15Mary Beth KneafseyNatural Environment Research Council (NERC)NE/J500252/1RSI - RESEARCH STRATEGY & INNOVATION