生公ㄟ啦是生母ㄟ?!
有趣味喔 生公ㄟ啦是生母ㄟ???!!! 真正有趣味喔 Elizabeth A. Krebs, David J. Green, Michael C. Double, Richard Griffiths 這幾位老大們, 在 Behavioral Ecology and Sociobiology 提到~~ 『下蛋的日期和下蛋的順序,會影響幼雛們之性別 』 觀察標的...一樣是紅草 有趣吶 以下為該段之摘要 敬請享用 Abstract: We examine the patterns of sex allocation in crimson rosellas Platycercus elegans, a socially monogamous Australian parrot. Overall, 41.8% of nestlings were male, a significant female bias. However underlying this population-level bias were non-random patterns of sex allocation within broods. Broods produced early in the season were female-biased, but the proportion of males in a brood increased as the breeding season progressed. Female rosellas may obtain greater fitness benefits from early-fledging daughters than sons because daughters can breed as 1-year-olds whereas sons do not breed until they are at least 2 years old. Laying date and laying sequence also interacted to influence the sex ratio of eggs. The sex of early-laid eggs strongly followed the brood level pattern, whereas the sex of middle- and late-laid eggs did not change significantly as the season progressed. Nevertheless, late-laid eggs were very unlikely to be male at the end of the season. We argue these differing seasonal patterns reflect the relative costs and benefits to producing early-hatched males and females at different times of the season. Female rosellas appear to maximise the probability that daughters are able to breed early but to minimise competitive asymmetries within the brood. In particular, late-hatched male chicks are disadvantaged if their oldest sibling is male, explaining the dearth of broods containing late-hatched males at the end of the breeding season.
