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Experimental evolution of external immune defences in the red flour beetle
Author(s) -
Joop G.,
Roth O.,
SchmidHempel P.,
Kurtz J.
Publication year - 2014
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.12406
Subject(s) - biology , immune system , host (biology) , immunity , innate immune system , pathogen , natural selection , offspring , microbiology and biotechnology , zoology , ecology , selection (genetic algorithm) , immunology , genetics , artificial intelligence , pregnancy , computer science
The red flour beetle, T ribolium castaneum , secretes quinones that control the microbial flora in the surrounding environment. These secretions act as an external immune defence that provides protection against pathogens. At high concentrations, however, these secretions are harmful to the host itself, and selection may thus have optimized the level of expression under natural conditions. Here, we show that the expression of external immunity responded to selection during experimental evolution within a few generations. At the same time, one component of internal immune defence (phenoloxidase activity) was compromised in beetles selected for either high or low external defences. Intriguingly, offspring protection against a natural pathogen was reduced in flour obtained from beetle lines selected for low amounts of secretions. Altogether, this suggests that external and internal immune defences work together efficiently under natural conditions, whereas every manipulation on the side of external immune defence comes with costs to the internal immune defence.