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A rare study from the wintering grounds provides insight into the costs of malaria infection for migratory birds

Sorensen, Marjorie C.; Asghar, Muhammad; Bensch, Staffan LU ; Fairhurst, Graham D.; Jenni-Eiermann, Susanne and Spottiswoode, Claire N. (2016) In Journal of Avian Biology 47(4). p.575-582
Abstract

Malaria parasites can have strong effects on the population dynamics and evolution of migratory bird species. In many species, parasite transmission occurs on the wintering grounds, but studies to determine the consequences of infection have taken place during the breeding season, when malaria parasites circulate at chronic levels. We examined the predictors of malarial infections for great reed warblers during the northern winter in Africa, where active parasite transmission is thought to occur and naïve individuals experience acute infections. Counter to expectations, we found that winter infection intensities were lower than those encountered on the breeding grounds. One potential explanation is that reduced immune function during... (More)

Malaria parasites can have strong effects on the population dynamics and evolution of migratory bird species. In many species, parasite transmission occurs on the wintering grounds, but studies to determine the consequences of infection have taken place during the breeding season, when malaria parasites circulate at chronic levels. We examined the predictors of malarial infections for great reed warblers during the northern winter in Africa, where active parasite transmission is thought to occur and naïve individuals experience acute infections. Counter to expectations, we found that winter infection intensities were lower than those encountered on the breeding grounds. One potential explanation is that reduced immune function during breeding allows parasites to persist at higher chronic intensities. We found no relationships between the incidence or intensity of infection on condition (as measured by scaled mass index, plasma metabolites, and feather corticosterone), spring migration departure dates, or home range sizes. We also tested a prediction of the Hamilton–Zuk hypothesis and found that male ornament (song) quality was unrelated to parasitic infection status. Overall, our results provide the first evidence that long-distance migrants captured on their wintering grounds are in the chronic stage of infection, and suggest that winter studies may fare no better than breeding studies at determining the costs of acute malarial infection for great reed warblers.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Avian Biology
volume
47
issue
4
pages
8 pages
publisher
Wiley-Blackwell
external identifiers
  • Scopus:84959450313
ISSN
0908-8857
DOI
10.1111/jav.00870
language
English
LU publication?
yes
id
7345a7ab-d80a-4c40-b802-7bf711d19804
date added to LUP
2016-09-22 08:25:32
date last changed
2016-11-14 09:43:04
@misc{7345a7ab-d80a-4c40-b802-7bf711d19804,
  abstract     = {<p>Malaria parasites can have strong effects on the population dynamics and evolution of migratory bird species. In many species, parasite transmission occurs on the wintering grounds, but studies to determine the consequences of infection have taken place during the breeding season, when malaria parasites circulate at chronic levels. We examined the predictors of malarial infections for great reed warblers during the northern winter in Africa, where active parasite transmission is thought to occur and naïve individuals experience acute infections. Counter to expectations, we found that winter infection intensities were lower than those encountered on the breeding grounds. One potential explanation is that reduced immune function during breeding allows parasites to persist at higher chronic intensities. We found no relationships between the incidence or intensity of infection on condition (as measured by scaled mass index, plasma metabolites, and feather corticosterone), spring migration departure dates, or home range sizes. We also tested a prediction of the Hamilton–Zuk hypothesis and found that male ornament (song) quality was unrelated to parasitic infection status. Overall, our results provide the first evidence that long-distance migrants captured on their wintering grounds are in the chronic stage of infection, and suggest that winter studies may fare no better than breeding studies at determining the costs of acute malarial infection for great reed warblers.</p>},
  author       = {Sorensen, Marjorie C. and Asghar, Muhammad and Bensch, Staffan and Fairhurst, Graham D. and Jenni-Eiermann, Susanne and Spottiswoode, Claire N.},
  issn         = {0908-8857},
  language     = {eng},
  month        = {07},
  number       = {4},
  pages        = {575--582},
  publisher    = {ARRAY(0x80d9cd0)},
  series       = {Journal of Avian Biology},
  title        = {A rare study from the wintering grounds provides insight into the costs of malaria infection for migratory birds},
  url          = {http://dx.doi.org/10.1111/jav.00870},
  volume       = {47},
  year         = {2016},
}