Experimental evolution reveals trade-offs between mating and immunity
Copright 2013 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited.
Immune system maintenance and upregulation is costly. Sexual selection intensity, which increases male investment into reproductive traits, is expected to create trade-offs with immune function. We assayed phenoloxidase (PO) and lytic activity of individuals from populations of the Indian meal moth, Plodia interpunctella, which had been evolving under different intensities of sexual selection. We found significant divergence among populations, with males from female-biased populations having lower PO activity than males from balanced sex ratio or male-biased populations. There was no divergence in anti-bacterial lytic activity. Our data suggest that it is the increased male mating demands in female-biased populations that trades-off against immunity, and not the increased investment in sperm transfer per mating that characterizes male-biased populations.
The study was supported by the Australian Research Council (K.B.M. and L.W.S.) and a Royal Society Wolfson Research Merit Award (N.W.). We thank Sheridan Willis and Michelle Hares for assistance.
This is the final version of the article. Available from the publisher via the DOI in this record.
Vol. 9: 20130262
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