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Survival costs of reproduction are mediated by parasite infection in wild Soay sheep
Author(s) -
Leivesley Jessica A.,
Bussière Luc F.,
Pemberton Josephine M.,
Pilkington Jill G.,
Wilson Kenneth,
Hayward Adam D.
Publication year - 2019
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/ele.13275
Subject(s) - biology , reproduction , ecology , zoology , population , reproductive success , life history theory , domestic sheep reproduction , parasite hosting , demography , life history , sociology , world wide web , computer science
A trade‐off between current and future fitness potentially explains variation in life‐history strategies. A proposed mechanism behind this is parasite‐mediated reproductive costs: individuals that allocate more resources to reproduction have fewer to allocate to defence against parasites, reducing future fitness. We examined how reproduction influenced faecal egg counts ( FEC ) of strongyle nematodes using data collected between 1989 and 2008 from a wild population of Soay sheep in the St. Kilda archipelago, Scotland (741 individuals). Increased reproduction was associated with increased FEC during the lambing season: females that gave birth, and particularly those that weaned a lamb, had higher FEC than females that failed to reproduce. Structural equation modelling revealed future reproductive costs: a positive effect of reproduction on spring FEC and a negative effect on summer body weight were negatively associated with overwinter survival. Overall, we provide evidence that parasite resistance and body weight are important mediators of survival costs of reproduction.