Non-random sex allocation may occur whenever the expected reproductive value of sons and daughters differs, as is the case when the sexes differ in susceptibility to environmental conditions or maternal effects (e.g. egg size and hatch order). Under such circumstances, covariation between egg and clutch characteristics and egg sex may be expected, and this covariation should vary with maternal state or ecological conditions. In this 2-year study (2007-2008), we examined sex allocation in relation to egg and clutch traits in the yellow-legged gull Larus michahellis, a species where male chicks are larger and more susceptible to harsh rearing conditions than female ones. In 2008, eggs were more likely male early in the season in two- but not three-egg clutches, and large eggs were more likely males late in the season. No egg/clutch traits predicted egg sex in 2007. Within-clutch egg mass asymmetry (the difference in egg mass between the first- and last-laid eggs) predicted sex in both years. In 2007, clutches with smaller egg mass variation were more likely to contain males, while in 2008 this relationship held for the last-laid egg and was reversed for the preceding egg(s). Laying order and sex of the previous egg did not predict egg sex, providing no evidence of sex-specific oocyte clustering. Thus, the relationships between egg sex and egg/clutch traits differed among years, suggesting a phenotypically plastic response of females to extrinsic conditions, and involved within-clutch egg mass asymmetry, a trait likely reflecting variation in maternal quality and/or reproductive tactics, which has been largely neglected in previous studies of sex allocation

Rubolini, D., Ambrosini, R., Romano, M., Caprioli, M., Fasola, M., Bonisoli Alquati, A., et al. (2009). Within-clutch egg size asymmetry covaries with embryo sex in the yellow-legged gull Larus michahellis. BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY, 63(12), 1809-1819 [10.1007/s00265-009-0808-4].

Within-clutch egg size asymmetry covaries with embryo sex in the yellow-legged gull Larus michahellis

AMBROSINI, ROBERTO;
2009

Abstract

Non-random sex allocation may occur whenever the expected reproductive value of sons and daughters differs, as is the case when the sexes differ in susceptibility to environmental conditions or maternal effects (e.g. egg size and hatch order). Under such circumstances, covariation between egg and clutch characteristics and egg sex may be expected, and this covariation should vary with maternal state or ecological conditions. In this 2-year study (2007-2008), we examined sex allocation in relation to egg and clutch traits in the yellow-legged gull Larus michahellis, a species where male chicks are larger and more susceptible to harsh rearing conditions than female ones. In 2008, eggs were more likely male early in the season in two- but not three-egg clutches, and large eggs were more likely males late in the season. No egg/clutch traits predicted egg sex in 2007. Within-clutch egg mass asymmetry (the difference in egg mass between the first- and last-laid eggs) predicted sex in both years. In 2007, clutches with smaller egg mass variation were more likely to contain males, while in 2008 this relationship held for the last-laid egg and was reversed for the preceding egg(s). Laying order and sex of the previous egg did not predict egg sex, providing no evidence of sex-specific oocyte clustering. Thus, the relationships between egg sex and egg/clutch traits differed among years, suggesting a phenotypically plastic response of females to extrinsic conditions, and involved within-clutch egg mass asymmetry, a trait likely reflecting variation in maternal quality and/or reproductive tactics, which has been largely neglected in previous studies of sex allocation
Articolo in rivista - Articolo scientifico
Clutch size, Egg quality, Sex allocation, Sex ratio, Trivers–Willard hypothesis
English
1809
1819
11
Rubolini, D., Ambrosini, R., Romano, M., Caprioli, M., Fasola, M., Bonisoli Alquati, A., et al. (2009). Within-clutch egg size asymmetry covaries with embryo sex in the yellow-legged gull Larus michahellis. BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY, 63(12), 1809-1819 [10.1007/s00265-009-0808-4].
Rubolini, D; Ambrosini, R; Romano, M; Caprioli, M; Fasola, M; Bonisoli Alquati, A; Saino, N
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/8503
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