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Sex allocation is color morph-specific and associated with fledging condition in a wild bird

Tooth, Amandine ; Morosinotto, Chiara LU and Karell, Patrik LU (2024) In Behavioral Ecology 35(4).
Abstract

Melanin-based color polymorphism is predicted to evolve and maintain through differential fitness of morphs in different environments, and several empirical studies indicate that life history strategies, physiology, and behavior vary among color morphs. Sex allocation theory predicts that parents should adjust their sex allocation based on differential costs of raising sons and daughters, and therefore, color morphs are expected to modify their brood sex ratio decisions. In color polymorphic tawny owls (Strix aluco), the pheomelanistic brown morph is associated with higher energy requirements, faster growth, and higher parental effort than the gray morph. As hypothesized, we find that brown tawny owl mothers produced more daughters in... (More)

Melanin-based color polymorphism is predicted to evolve and maintain through differential fitness of morphs in different environments, and several empirical studies indicate that life history strategies, physiology, and behavior vary among color morphs. Sex allocation theory predicts that parents should adjust their sex allocation based on differential costs of raising sons and daughters, and therefore, color morphs are expected to modify their brood sex ratio decisions. In color polymorphic tawny owls (Strix aluco), the pheomelanistic brown morph is associated with higher energy requirements, faster growth, and higher parental effort than the gray morph. As hypothesized, we find that brown tawny owl mothers produced more daughters in early broods and more males in late broods, whereas gray mothers did the opposite. At fledging, daughters of early broods and of brown mothers were heavier than those of late broods or gray mothers. Hence, larger and more costly daughters appeared to benefit more than males from being born to brown mothers early in the season. Brown mothers breeding later in the season produced more cheap sons, while gray mothers face fewer challenges under limited resources and favor daughters. These findings suggest that environmental conditions influence brood sex allocation strategies of genetically determined color morphs differently.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
early life condition, fitness, genetic polymorphism, life history strategy, melanism, reproductive trade-off, sex ratio
in
Behavioral Ecology
volume
35
issue
4
article number
arae039
publisher
Oxford University Press
external identifiers
  • scopus:85194965638
  • pmid:38818250
ISSN
1045-2249
DOI
10.1093/beheco/arae039
language
English
LU publication?
yes
id
f0e4e2c0-0bf0-47e5-b025-9a960b232bb3
date added to LUP
2024-11-07 10:36:35
date last changed
2025-07-04 07:03:17
@article{f0e4e2c0-0bf0-47e5-b025-9a960b232bb3,
  abstract     = {{<p>Melanin-based color polymorphism is predicted to evolve and maintain through differential fitness of morphs in different environments, and several empirical studies indicate that life history strategies, physiology, and behavior vary among color morphs. Sex allocation theory predicts that parents should adjust their sex allocation based on differential costs of raising sons and daughters, and therefore, color morphs are expected to modify their brood sex ratio decisions. In color polymorphic tawny owls (Strix aluco), the pheomelanistic brown morph is associated with higher energy requirements, faster growth, and higher parental effort than the gray morph. As hypothesized, we find that brown tawny owl mothers produced more daughters in early broods and more males in late broods, whereas gray mothers did the opposite. At fledging, daughters of early broods and of brown mothers were heavier than those of late broods or gray mothers. Hence, larger and more costly daughters appeared to benefit more than males from being born to brown mothers early in the season. Brown mothers breeding later in the season produced more cheap sons, while gray mothers face fewer challenges under limited resources and favor daughters. These findings suggest that environmental conditions influence brood sex allocation strategies of genetically determined color morphs differently.</p>}},
  author       = {{Tooth, Amandine and Morosinotto, Chiara and Karell, Patrik}},
  issn         = {{1045-2249}},
  keywords     = {{early life condition; fitness; genetic polymorphism; life history strategy; melanism; reproductive trade-off; sex ratio}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{4}},
  publisher    = {{Oxford University Press}},
  series       = {{Behavioral Ecology}},
  title        = {{Sex allocation is color morph-specific and associated with fledging condition in a wild bird}},
  url          = {{http://dx.doi.org/10.1093/beheco/arae039}},
  doi          = {{10.1093/beheco/arae039}},
  volume       = {{35}},
  year         = {{2024}},
}