Female-biased mortality in experimentally parasitized Alpine Swift Apus melba nestlings

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Serval ID
serval:BIB_6FE44C79624A
Type
Article: article from journal or magazin.
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Publications
Institution
Title
Female-biased mortality in experimentally parasitized Alpine Swift Apus melba nestlings
Journal
Functional Ecology
Author(s)
Bize P., Roulin A., Tella J. L., Richner H.
ISSN
0269-8463
Publication state
Published
Issued date
2005
Peer-reviewed
Oui
Volume
19
Number
3
Pages
405-413
Language
english
Abstract
1. Sex-biased mortality in adult vertebrates is often attributed to lower immunocompetence and higher parasite susceptibility of males. Although sex-specific mortality has also been reported during growth, the importance of sex-specific immunocompetence and parasite susceptibility in explaining male-biased mortality remains ambiguous in growing individuals because of potentially confounding sources of mortality such as sexual dimorphism.
2. Here, we investigated sex-specific susceptibility to the blood-sucking louse fly Crataerina melbae and sex differences in cell-mediated immunity in a bird species that is sexually monomorphic both in size and plumage coloration at the nestling stage, the Alpine Swift, Apus melba.
3. For this purpose, we manipulated ectoparasite loads by adding or removing flies to randomly chosen nests in two years, and injected nestlings with mitogenic phytohaemagglutinin (PHA) in another year.
4. There were no significant differences between male and female offspring in immune response towards PHA, parasite load, and parasite-induced decrease in growth rate. Secondary sex ratios were however biased toward males in parasitized broods, and this was explained by a greater mortality of females in parasitized than deparasitized broods.
5. Our findings are in contrast to the widely accepted hypothesis that males suffer a greater cost of parasitism. We discuss alternative hypotheses accounting for female-specific mortality.
Keywords
Hippoboscidae, immunocompetence, phytohaematogglutinin, sex-specific mortality, sibling competition
Web of science
Open Access
Yes
Create date
24/01/2008 18:42
Last modification date
20/08/2019 15:28
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