摘要
Females may favour some offspring over others by differential deposition of yolk hormones. In American kestrels (Falco sparverius), we found that yolks of eggs laid late in the sequence of a clutch had more testosterone (T) and androstenedione (A4) than yolks of first–laid eggs. To investigate the effects of these yolk androgens on nestling ‘fitness’, we injected both T and A4 into the yolks of first–laid eggs and compared their hatching time, nestling growth and nestling survival with those of first–laid eggs in which we injected vehicle as a control. Compared to controls, injection of T and A4 at a dose intended to increase their levels to those of later–laid eggs delayed hatching and reduced nestling growth and survival rates. Yolk androgen treatment of egg 1 had no effect on survival of siblings hatching from subsequently laid eggs. The adverse actions of yolk androgen treatment in the kestrel are in contrast to the favourable actions of yolk T treatment found previously in canaries (Serinus canaria). Additional studies are necessary in order to determine whether the deposition of yolk androgens is an adaptive form of parental favouritism or an adverse by–product of endocrine processes during egg formation. Despite its adaptive significance, such ‘transgenerational’ effects of steroid hormones may have helped to evolutionarily shape the hormonal mechanisms regulating reproduction.
摘要译文
女性可能通过蛋黄激素的差异沉积来支持一些其他人的后代。在美国的kestrels（Falco sparverius），我们发现，离合器序列较晚的蛋卵蛋黄比初次卵的卵子有更多的睾酮（T）和雄烯二酮（A 4）。为了研究这些卵黄雄激素对雏鸟“适应性”的影响，我们将T和A 4都注入到初卵的蛋黄中，并比较其孵化时间，雏鸟生长和雏鸟生存与我们注射车辆作为对照的第一胎鸡蛋生长。与对照相比，以剂量的方式注射T和A 4，以增加其水平与晚产卵的水平延迟孵化和减少雏鸟生长和存活率。鸡蛋1的卵黄雄激素处理对来自随后产卵的兄弟孵化的存活没有影响。蛋黄雄激素治疗在蜈蚣中的不利行为与以前在金丝雀（丝状丝氨酸）加拿大发现的卵黄T治疗的有利作用形成对照。为了确定蛋黄雄激素的沉积是否是卵形成过程中亲本偏倚或内分泌过程的不利副产物的适应形式，必须进行研究。尽管它具有适应性的意义，但类固醇激素的这种“跨代”效应可能有助于进化地调节繁殖的激素机制。
Keith W. Sockman;Hubert Schwabl[1]. Yolk androgens reduce offspring survival[J]. Proceedings of the Royal Society of London B: Biological Sciences, 2000,267(1451)