Abstract：
Mothers who produce multiple offspring within one reproductive attempt often allocate resources differentially; some maternally derived substances are preferentially allocated to last-produced offspring and others to first-produced offspring. The combined effect of these different allocation regimes on the overall fitness of offspring produced early or late in the sequence is not well understood, partly because production order is often coupled with birth order, making it difficult-to-separate effects of pre-natal maternal allocation from those of post-natal social environments. In addition, very little is known about the influence of laying order on fitness in later life. In this study, we used a semi-natural captive colony of black-headed gulls to test whether an offspring\'s position in the laying order affected its early-life survival and later-life reproductive success, independent of its hatching order. Later-laid eggs were less likely to hatch, but among those that did, survival to adulthood was greater than that of first-laid eggs. In adulthood, the laying order of females did not affect their likelihood of breeding in the colony, but male offspring hatched from last-laid eggs were significantly less likely to gain a breeding position than earlier-laid males. In contrast, later-laid female parents hatched lower proportions of their clutches than first-laid females, but hatching success was unrelated to the laying order of male parents. Our results indicate that gull mothers induce complex and sex-specific effects on both the early survival of their offspring and on long-term reproductive success through laying order effects among eggs of the same breeding attempt.
摘要：
在一次生殖尝试中产生多个后代的母亲通常会差异分配资源；一些母本来源的物质优先分配给最后产生的后代，其他物质优先分配给首次产生的后代。这些不同的分配制度对序列早期或晚期产生的后代的整体适应性的综合影响尚不清楚，部分原因是生产顺序通常与出生顺序相结合，很难将产前产妇分配的影响与产后社会环境的影响分开。此外,很少有人知道在以后的生活中铺设顺序对健身的影响。在这项研究中,我们使用了半自然圈养的黑头海鸥群体来测试后代在产卵顺序中的位置是否影响其早期生存和后期繁殖的成功，独立于其孵化顺序。后来产下的卵不太可能孵化，但是在那些这样做的人中，成年期的存活率大于初产的卵。成年后,雌性的产卵顺序并不影响它们在殖民地繁殖的可能性，但是，从最后产卵孵化出的雄性后代获得繁殖位置的可能性明显低于早期产卵的雄性。相比之下,后来出生的女性父母孵化出的离合器比例低于初睡的女性，但是孵化成功与男性父母的产卵顺序无关。我们的结果表明，海鸥母亲通过在相同育种尝试的卵中产下顺序效应，对后代的早期存活和长期繁殖成功都产生了复杂的和性别特异性的影响。
