Sexual dimorphism in house sparrow eggs

Cordero, Pedro J.; Griffith, Simon C.; Aparicio, José Miguel; Parkin, David T.

doi:10.1007/s002650000252

Cited by 104 publications

(111 citation statements)

References 29 publications

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“…A possible explanation for our results is sexual dimorphism of egg size, which has been previously reported in various avian species (e.g., American kestrel, Falco sparverius: Anderson et al, 1997; house sparrow, Passer domesticus: Cordero et al, 2000;brown songlark: Magrath et al, 2003). However, we did not find any differences in egg mass between offspring sexes (Two-sample t test: t = 0.227, p = 0.820; male egg mass: mean ± SD = 1.065 ± 0.073 g, N = 63; female egg mass ± SD = 1.062 ± 0.091 g, N = 56), indicating that heavier eggs did not necessarily contain sons.…”

Section: Discussionmentioning

confidence: 51%

Differential allocation in relation to mate song quality in the Bengalese finch

Soma

Okanoya

2013

Behav

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Postmating sexual selection plays an important part in the evolution of secondary sexual characters. Based on differential allocation theory that predicts biased reproductive investment of females depending on the attractiveness of mates, a number of previous studies have shown that egg production is related in various ways to ornamental sexual traits of males, but evidence for behavioral sexual traits is less abundant. In this study we examine such maternal effects in relation to birdsong.Because the Bengalese finch is a monomorphic songbird, courtship song serves a key role in mate choice. To take into account individual female differences in egg production performance, we sequentially paired naïve, captive, female Bengalese finches to two different males, and investigated if their reproductive investment (clutch size, egg mass and hatchling sex ratio) was related to the song traits of their mates. We found that clutch size and egg mass were highly repeatable within individual females while sex ratio was not. Despite the inflexibility of egg mass within each female, egg mass increased when females were mated to males with longer songs. In addition, we found a non-significant weak tendency toward male-biased sex ratio in relation to longer song duration of mates. Our findings suggest that females mated to better mates adjusted their reproductive investment by producing heavier eggs and possibly offspring of the more costly sex.

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Section: Discussionmentioning

confidence: 51%

Differential allocation in relation to mate song quality in the Bengalese finch

Soma

Okanoya

2013

Behav

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“…The size difference observed between male and female eggs is thus more probably due to a sex-specific egg provisioning, rather than to a differential mortality between the two sexes. This differential investment in eggs of each sex has been observed in birds, such as the American kestrel or the Bengalese finch, with male eggs larger than female eggs, probably to compensate for the greater vulnerability of males to sibling competition [22][23][24][25][26][27][28]. However, egg sexual dimorphism has never been investigated so far in haplodiploids, except in the predatory mite Phytoseiulus persimilis, where female eggs were also found to be larger than male eggs [30].…”

Section: Discussion (A) Variation Of Egg Size Affects Offspring Fitnementioning

confidence: 93%

“…However, very few studies have investigated the adjustment of egg size depending on the sex of the embryo. Such sex-biased parental strategies have been demonstrated in birds [22][23][24][25][26][27][28] and recently in a lizard [29], but so far only a single study has addressed this question in haplodiploid arthropods [30], although they are key models in the study of sex allocation.…”

Section: Introductionmentioning

confidence: 99%

Sex allocation in haplodiploids is mediated by egg size: evidence in the spider mite Tetranychus urticae Koch

et al. 2010

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Haplodiploid species display extraordinary sex ratios. However, a differential investment in male and female offspring might also be achieved by a differential provisioning of eggs, as observed in birds and lizards. We investigated this hypothesis in the haplodiploid spider mite Tetranychus urticae, which displays highly female-biased sex ratios. We show that egg size significantly determines not only larval size, juvenile survival and adult size, but also fertilization probability, as in marine invertebrates with external fertilization, so that female (fertilized) eggs are significantly larger than male (unfertilized) eggs. Moreover, females with on average larger eggs before fertilization produce a more female-biased sex ratio afterwards. Egg size thus mediates sex-specific egg provisioning, sex and offspring sex ratio. Finally, sex-specific egg provisioning has another major consequence: male eggs produced by mated mothers are smaller than male eggs produced by virgins, and this size difference persists in adults. Virgin females might thus have a (male) fitness advantage over mated females.

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“…In fact, variation in egg components has been shown to be related to offspring sex (Anderson et al 1997;Cordero et al 2000Cordero et al , 2001Cunningham & Russell 2001). This intrepretation, however, is unlikely because in another experiment there was no effect of tail manipulation on progeny sex ratio (Saino et al 1999b).…”

Section: Discussionmentioning

confidence: 99%

Early maternal effects mediated by immunity depend on sexual ornamentation of the male partner

Saino

Ferrari

Martinelli

et al. 2002

Proc. R. Soc. Lond. B

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Vertebrates have an immature immune system soon after birth, and parasites can therefore be particularly virulent to young hosts. Transfer of immune factors via the egg can give rise to early maternal effects with important consequences for offspring ® tness, as maternally derived immunity confers anti-parasite protection. Mothers are expected to allocate immunity differentially to the eggs according to the reproductive value of their offspring as in¯uenced by the quality of their father. In this study, we analysed transmission to the yolk of antibodies speci® c to an antigen (Newcastle disease virus vaccine, NDV) by vaccinated female barn swallows (Hirundo rustica) mated to males whose secondary sexual characteristics had been manipulated. Concentration of anti-NDV antibodies in the yolk positively covaried with that in maternal plasma. Anti-NDV antibodies were more concentrated in the ® rst but not the fourth eggs laid by females mated with tail-elongated males compared with those mated with tail-shortened and control males. This experiment shows that allocation of maternal immune factors to the eggs is affected by quality of the male, as signalled by its secondary sexual characteristic. Thus, early maternal effects are in¯uenced by sexual attractiveness of male mates and are mediated by immunity.

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Sexual dimorphism in house sparrow eggs

Cited by 104 publications

References 29 publications

Differential allocation in relation to mate song quality in the Bengalese finch

Differential allocation in relation to mate song quality in the Bengalese finch

Sex allocation in haplodiploids is mediated by egg size: evidence in the spider mite Tetranychus urticae Koch

Early maternal effects mediated by immunity depend on sexual ornamentation of the male partner

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