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Variation in body condition of breeding Savi's Warblers Locustella luscinioides: the reproductive stress and flight adaptation hypothesis revisited

Neto, Julio LU and Gosler, Andrew G. (2010) In Journal für Ornithologie1852-12-31+01:002004-01-01+01:00 151(1). p.201-210
Abstract
Current theory suggests that mass change in adult birds while breeding may be adaptive (to reduce wing-loading during nestling feeding) or result from physiological stress. To test which might be more important in determining mass loss in breeding Savi's Warblers (Locustella luscinioides), we used a new approach in which the variation in four indices of body condition was described: weight, fat score, muscle score and lean weight (i.e. excluding fat and muscle). We expected weight variations to be adaptive if they involved changes in fat and lean weight, whereas physiological stress should influence the muscle score to a greater extent. As in other species, females showed a greater variation in weight, and carried more fat, than males... (More)
Current theory suggests that mass change in adult birds while breeding may be adaptive (to reduce wing-loading during nestling feeding) or result from physiological stress. To test which might be more important in determining mass loss in breeding Savi's Warblers (Locustella luscinioides), we used a new approach in which the variation in four indices of body condition was described: weight, fat score, muscle score and lean weight (i.e. excluding fat and muscle). We expected weight variations to be adaptive if they involved changes in fat and lean weight, whereas physiological stress should influence the muscle score to a greater extent. As in other species, females showed a greater variation in weight, and carried more fat, than males during the breeding cycle. During incubation, females had greater weight and fat score than males. The weight remained constant and lean weight declined in both sexes, whereas females increased in muscle, which probably reflects the regression of the reproductive organs. During the nestling stage, both sexes declined significantly in all four indices of condition, showing evidence of physiological stress. However, the greater decline in weight in females than in males is consistent with the flight-adaptation hypothesis, as are the cyclic changes in lean weight associated with the various nesting attempts. The fact that both sexes declined significantly in weight, muscle and lean weight with an increasing number of nesting attempts, but not in fat, which was recovered after each nestling period, also indicates that both reproductive stress and adaptive changes occur during breeding. When the whole breeding season was considered, females showed a greater decline in muscle than males, which we interpret to be evidence for a greater reproductive stress in females. We suggest that the small breast muscle size and depleted protein reserves at the end of the breeding period might influence future survival through impaired flight ability and a compromised post-breeding moult. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Body condition, Fat, Muscle, Physiological stress, Reproduction
in
Journal für Ornithologie1852-12-31+01:002004-01-01+01:00
volume
151
issue
1
pages
201 - 210
publisher
Springer
external identifiers
  • wos:000273034100024
  • scopus:77952955311
ISSN
1439-0361
DOI
10.1007/s10336-009-0444-9
language
English
LU publication?
yes
id
03c3b5f0-839f-4e66-a14d-be8a1f481581 (old id 1533826)
date added to LUP
2010-01-27 14:28:27
date last changed
2018-06-17 04:02:49
@article{03c3b5f0-839f-4e66-a14d-be8a1f481581,
  abstract     = {Current theory suggests that mass change in adult birds while breeding may be adaptive (to reduce wing-loading during nestling feeding) or result from physiological stress. To test which might be more important in determining mass loss in breeding Savi's Warblers (Locustella luscinioides), we used a new approach in which the variation in four indices of body condition was described: weight, fat score, muscle score and lean weight (i.e. excluding fat and muscle). We expected weight variations to be adaptive if they involved changes in fat and lean weight, whereas physiological stress should influence the muscle score to a greater extent. As in other species, females showed a greater variation in weight, and carried more fat, than males during the breeding cycle. During incubation, females had greater weight and fat score than males. The weight remained constant and lean weight declined in both sexes, whereas females increased in muscle, which probably reflects the regression of the reproductive organs. During the nestling stage, both sexes declined significantly in all four indices of condition, showing evidence of physiological stress. However, the greater decline in weight in females than in males is consistent with the flight-adaptation hypothesis, as are the cyclic changes in lean weight associated with the various nesting attempts. The fact that both sexes declined significantly in weight, muscle and lean weight with an increasing number of nesting attempts, but not in fat, which was recovered after each nestling period, also indicates that both reproductive stress and adaptive changes occur during breeding. When the whole breeding season was considered, females showed a greater decline in muscle than males, which we interpret to be evidence for a greater reproductive stress in females. We suggest that the small breast muscle size and depleted protein reserves at the end of the breeding period might influence future survival through impaired flight ability and a compromised post-breeding moult.},
  author       = {Neto, Julio and Gosler, Andrew G.},
  issn         = {1439-0361},
  keyword      = {Body condition,Fat,Muscle,Physiological stress,Reproduction},
  language     = {eng},
  number       = {1},
  pages        = {201--210},
  publisher    = {Springer},
  series       = {Journal für Ornithologie1852-12-31+01:002004-01-01+01:00},
  title        = {Variation in body condition of breeding Savi's Warblers Locustella luscinioides: the reproductive stress and flight adaptation hypothesis revisited},
  url          = {http://dx.doi.org/10.1007/s10336-009-0444-9},
  volume       = {151},
  year         = {2010},
}