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.

这项研究通过实验检验了倒置水母与其藻类共生体之间的共生关系。这种互利共生以及共生体的传染性传播代表了一类共生体的合作仍然无法解释。选择实验提出了维持共生体合作的两个对立假设：伙伴忠诚度，其中伙伴之间的重复互动有利于合作者而不是作弊者和伙伴选择，其中宿主可以有差别地奖励合作共生体和/或惩罚作弊者。宿主之间的共生传播是通过实验操纵的；一种治疗方法强制传染性传播——在不相关的宿主之间（选择作弊），另一种治疗方法强制传播——在父母和后代之间（选择合作）。对实验进化的宿主和共生体的适应度测定将解决伴侣选择或伴侣忠诚是否稳定了这种共生中的合作，以及自然界中是否存在作弊共生体。共生体感染性传播的互惠关系是生物学中尚未解决的问题。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，大自然中充满了互利共生，其中共生体是水平获得的。此外，水母和相关珊瑚的白化代表了这种互利共生的一个具有重要生态意义但人们对此知之甚少的崩溃。这项研究有望帮助揭示这些人们知之甚少的共生体的进化维持。