Johnson Collin H
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Biol Bull. 2010 Aug;219(1):27-37. doi: 10.1086/BBLv219n1p27.
Understanding the consequences of selfing in simultaneous hermaphrodites requires investigating potential deleterious effects on fitness at all stages of life. In this study, I examined the effects of selfing throughout the life cycle of the marine bryozoan Bugula stolonifera, a colonial simultaneous hermaphrodite. In 2008, larvae from field-collected colonies were cultured through metamorphosis to reproductively mature colonies either in the presence of one other colony, the paired treatment, or alone, the solitary treatment. Results demonstrated that selfing in this species is possible, in that colonies in the solitary treatment produced viable larvae that successfully completed metamorphosis. On average, however, these colonies released significantly fewer larvae, which experienced reduced rates of metamorphic initiation and completion compared to the paired treatment. These experiments were extended in 2009, when metamorphs from colonies reared in the solitary (n = 58) and paired (n = 61) treatments were transferred to the field for growth to reproductive maturity and then brought back to the laboratory for larval collection. Results revealed additional deleterious effects associated with selfing, as no viable larvae were recovered from colonies deriving from the solitary treatment. In contrast, offspring from the paired treatment released 1030 larvae and 99% initiated metamorphosis, 97% of which completed metamorphosis. Overall, selfed larvae not only had significantly decreased chances of survival, but those that did survive did not successfully reproduce.
了解雌雄同体生物自交的后果需要研究其在生命各个阶段对适合度的潜在有害影响。在本研究中，我研究了海洋苔藓虫Bugula stolonifera（一种群体雌雄同体生物）整个生命周期中自交的影响。2008年，将从野外采集的群体中获得的幼虫培养至变态，使其发育为生殖成熟的群体，培养过程中，一部分幼虫与另一个群体共同培养（配对处理），另一部分单独培养（单独处理）。结果表明，该物种能够进行自交，因为单独处理的群体产生了能够成功完成变态的有活力的幼虫。然而，平均而言，这些群体释放的幼虫数量显著减少，与配对处理相比，其变态起始和完成的速率降低。2009年，这些实验得到了扩展，将单独处理（n = 58）和配对处理（n = 61）培养出的变态体转移到野外生长至生殖成熟，然后带回实验室收集幼虫。结果揭示了与自交相关的其他有害影响，因为从单独处理的群体中未获得有活力的幼虫。相比之下，配对处理的后代释放了1030只幼虫，其中99%开始变态，97%完成变态。总体而言，自交产生的幼虫不仅存活几率显著降低，而且那些存活下来的幼虫也未能成功繁殖。
