Hughes R N, Manríquez P H, Bishop J D D, Burrows M T
School of Biological Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, United Kingdom.
Proc Natl Acad Sci U S A. 2003 Sep 2;100(18):10326-30. doi: 10.1073/pnas.1334011100. Epub 2003 Aug 20.
Sex-allocation theory developed for hermaphroditic plants predicts that impaired phenotype or reduced parental survivorship caused by environmental stress should induce relatively greater allocation to the male function. We provide experimental evidence of stress-induced maleness, already well documented in flowering plants, in a modular animal. By using cloned copies of replicate genotypes, we show that the marine bryozoan Celleporella hyalina increases the ratio of male to female modules in response to diverse environmental stressors. Mating trials confirmed that paternity is determined by fair-raffle sperm competition, which should obviate local mate competition at characteristic population density and promote the advantage of increased male allocation. The demonstrated similarity to plants transcends specific physiological pathways and suggests that stress-induced bias toward male function is a general response of hermaphroditic modular organisms to impaired prospects for parental productivity or survival.
为雌雄同体植物所发展出的性别分配理论预测，由环境压力导致的表型受损或亲代存活率降低，应会促使对雄性功能的分配相对增加。我们在一种模块化动物中提供了压力诱导雄性化的实验证据，这种现象在开花植物中已有充分记载。通过使用重复基因型的克隆副本，我们表明，海洋苔藓虫透明膜孔苔虫会响应多种环境压力源，增加雄性模块与雌性模块的比例。交配试验证实，父权由公平抽奖式精子竞争决定，这应能消除在特征性种群密度下的局部配偶竞争，并促进增加雄性分配的优势。所证明的与植物的相似性超越了特定的生理途径，表明压力诱导的对雄性功能的偏向是雌雄同体模块化生物对亲代生产力或生存前景受损的一种普遍反应。
