DISSERTATION RESEARCH: Experimental Selection for Cheating in a Mutualistic Symbiont

论文研究：互利共生体中作弊的实验选择

• 批准号: 0308780
• 负责人: James Bull
• 金额: $ 0.92万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0308780&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Experimental; Selection; Cheating

This study experimentally examines the symbiosis between the upside-down jellyfish and its algal symbiont. This mutualism, with infectious transmission of symbionts, represents a class of symbioses for which symbiont cooperation remains unexplained. A selection experiment addresses two opposing hypotheses for the maintenance of symbiont cooperation: Partner fidelity, in which repeated interactions between partners favors cooperators over cheaters and partner choice, in which hosts can differentially reward cooperating symbionts and/or punish cheaters. Symbiont transmission between hosts is experimentally manipulated; one treatment enforces infectious transmission- between unrelated hosts (selection for cheating ) and the other vertical transmission- between parent and offspring (selection for cooperation). Fitness assays on experimentally evolved hosts and symbionts will resolve whether partner choice or partner fidelity stabilizes cooperation in this symbiosis and whether cheater symbionts exist in nature.Mutualisms with infectious transmission of symbionts are an unsolved problem in biology. Theory states that while vertical transmission of symbionts favors cooperation, infectious transmission favors parasitism. Nonetheless, nature abounds with mutualisms in which the symbionts are horizontally acquired. Furthermore, bleaching in jellyfish and related corals represents an ecologically important, yet poorly understood breakdown of this mutualism. This study promises to help unravel the evolutionary maintenance of these poorly understood symbioses.

本研究以实验方式探讨倒置水母与其藻类共生体之间的共生关系。这种互惠共生，伴随着共生体的传染性传播，代表了一类共生体合作仍然无法解释的共生现象。一个选择实验解决了两个对立的假设共生体合作的维护：合作伙伴的忠诚度，其中合作伙伴之间的重复互动有利于合作者对骗子和合作伙伴的选择，其中主机可以有区别地奖励合作的共生体和/或惩罚骗子。宿主之间的共生体传播是通过实验来控制的;一种处理方法是在不相关的宿主之间（选择欺骗）强制传染性传播，另一种处理方法是在父母和后代之间（选择合作）强制垂直传播。通过对实验进化的宿主和共生体进行适合度分析，可以确定共生体中是否存在配偶选择或配偶忠诚度来稳定合作关系，以及是否存在欺骗性共生体。理论指出，虽然共生体的垂直传播有利于合作，但感染性传播有利于寄生。尽管如此，自然界充满了互惠共生，其中共生体是水平获得的。此外，水母和相关珊瑚的白化是一种重要的生态学现象，但对这种共生关系的破坏却知之甚少。这项研究有望帮助解开这些鲜为人知的共生体的进化维持。