Immune Activation Reduces Sperm Quality in the Great Tit

Losdat, Sylvain; Richner, Heinz; Blount, Jonathan D.; Helfenstein, Fabrice (2011). Immune Activation Reduces Sperm Quality in the Great Tit. PLoS ONE, 6(7), e22221. Lawrence, Kans.: Public Library of Science 10.1371/journal.pone.0022221

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Mounting an immune response against pathogens incurs costs to organisms by its effects on important life-history traits, such as reproductive investment and survival. As shown recently, immune activation produces large amounts of reactive species and is suggested to induce oxidative stress. Sperm are highly susceptible to oxidative stress, which can negatively impact sperm function and ultimately male fertilizing efficiency. Here we address the question as to whether mounting an immune response affects sperm quality through the damaging effects of oxidative stress. It has been demonstrated recently in birds that carotenoid-based ornaments can be reliable signals of a male's ability to protect sperm from oxidative damage. In a full-factorial design, we immune-challenged great tit males while simultaneously increasing their vitamin E availability, and assessed the effect on sperm quality and oxidative damage. We conducted this experiment in a natural population and tested the males' response to the experimental treatment in relation to their carotenoid-based breast coloration, a condition-dependent trait. Immune activation induced a steeper decline in sperm swimming velocity, thus highlighting the potential costs of an induced immune response on sperm competitive ability and fertilizing efficiency. We found sperm oxidative damage to be negatively correlated with sperm swimming velocity. However, blood resistance to a free-radical attack (a measure of somatic antioxidant capacity) as well as plasma and sperm levels of oxidative damage (lipid peroxidation) remained unaffected, thus suggesting that the observed effect did not arise through oxidative stress. Towards the end of their breeding cycle, swimming velocity of sperm of more intensely colored males was higher, which has important implications for the evolution of mate choice and multiple mating in females because females may accrue both direct and indirect benefits by mating with males having better quality sperm.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE)
08 Faculty of Science > Department of Biology > Institute of Ecology and Evolution (IEE) > Evolutionary Ecology

UniBE Contributor:

Losdat, Sylvain; Richner, Heinz and Helfenstein, Fabrice Noël

ISSN:

1932-6203

Publisher:

Public Library of Science

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:27

Last Modified:

13 Dec 2014 13:36

Publisher DOI:

10.1371/journal.pone.0022221

Web of Science ID:

000292699000031

BORIS DOI:

10.7892/boris.10077

URI:

https://boris.unibe.ch/id/eprint/10077 (FactScience: 215912)

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