No apparent cost of evolved immune response in Drosophila melanogaster
Maintenance and deployment of the immune system are costly and are hence predicted to trade-off with other resource-demanding traits, such as reproduction. We subjected this longstanding idea to test using laboratory experimental evolution approach. In the present study, replicate populations of Dro...
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Published in | Evolution Vol. 70; no. 4; pp. 934 - 943 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Blackwell Publishing Ltd
01.04.2016
Society for the Study of Evolution Oxford University Press |
Subjects | |
Online Access | Get full text |
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Summary: | Maintenance and deployment of the immune system are costly and are hence predicted to trade-off with other resource-demanding traits, such as reproduction. We subjected this longstanding idea to test using laboratory experimental evolution approach. In the present study, replicate populations of Drosophila melanogaster were subjected to three selection regimes—I (Infection with Pseudomonas entomophila), S (Sham-infection with MgSO4), and U (Unhandled Control). After 30 generations of selection files from the I regime had evolved better survivorship upon infection with P. entomophila compared to flies from U and S regimes. However, contrary to expectations and previous reports, we did not find any evidence of trade-offs between immunity and other life history related traits, such as longevity, fecundity, egg hatchability, or development time. After 45 generations of selection, the selection was relaxed for a set of populations. Even after 15 generations. the postinfection survivorship of populations under relaxed selection regime did not decline. We speculate that either there is a negligible cost to the evolved immune response or that trade-offs occur on traits such as reproductive behavior or other immune mechanisms that we have not investigated in this study. Our research suggests that at least under certain conditions, life-history trade-offs might play little role in maintaining variation in immunity. |
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Bibliography: | istex:18DAEAABC6E587DC1DDD10E02E7B12663877C9AF ark:/67375/WNG-18CQJ9V4-L ArticleID:EVO12896 Table S1. Summary of results of mixed effects model ANOVA on life history traits - (a) longevity, (b) development time, and (c) fecundity. Table S2. Summary of results of Cox Proportional Hazards model performed on longevity post-infection (Data from generation 33). Table S3a. Summary of results of Cox Proportional Hazards model performed on longevity under uninfected condition. Table S3b. Summary of results of Cox Proportional Hazards model performed on longevity under infected condition. Table S4. Results from three - way ANOVA performed on the difference in proportion survived between I and S. Figure S1. Life-history traits in selected and control populations. Figure S2. Post-infection survivorship difference between I and S. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0014-3820 1558-5646 |
DOI: | 10.1111/evo.12896 |