TY - JOUR
T1 - Sex allocation is color morph-specific and associated with fledging condition in a wild bird
AU - Tooth, Amandine
AU - Morosinotto, Chiara
AU - Karell, Patrik
PY - 2024/7/1
Y1 - 2024/7/1
N2 - 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.
AB - 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.
KW - early life condition
KW - fitness
KW - genetic polymorphism
KW - life history strategy
KW - melanism
KW - reproductive trade-off
KW - sex ratio
U2 - 10.1093/beheco/arae039
DO - 10.1093/beheco/arae039
M3 - Article
C2 - 38818250
AN - SCOPUS:85194965638
SN - 1045-2249
VL - 35
JO - Behavioral Ecology
JF - Behavioral Ecology
IS - 4
M1 - arae039
ER -