Jones Emily I, Afkhami Michelle E, Akçay Erol, Bronstein Judith L, Bshary Redouan, Frederickson Megan E, Heath Katy D, Hoeksema Jason D, Ness Joshua H, Pankey M Sabrina, Porter Stephanie S, Sachs Joel L, Scharnagl Klara, Friesen Maren L
Department of BioSciences, Rice University, Houston, TX, 77005, USA.
Wissenschaftskolleg zu Berlin, Institute for Advanced Study, 14193, Berlin, Germany.
Ecol Lett. 2015 Nov;18(11):1270-1284. doi: 10.1111/ele.12507. Epub 2015 Sep 21.
Cheating is a focal concept in the study of mutualism, with the majority of researchers considering cheating to be both prevalent and highly damaging. However, current definitions of cheating do not reliably capture the evolutionary threat that has been a central motivation for the study of cheating. We describe the development of the cheating concept and distill a relative-fitness-based definition of cheating that encapsulates the evolutionary threat posed by cheating, i.e. that cheaters will spread and erode the benefits of mutualism. We then describe experiments required to conclude that cheating is occurring and to quantify fitness conflict more generally. Next, we discuss how our definition and methods can generate comparability and integration of theory and experiments, which are currently divided by their respective prioritisations of fitness consequences and traits. To evaluate the current empirical evidence for cheating, we review the literature on several of the best-studied mutualisms. We find that although there are numerous observations of low-quality partners, there is currently very little support from fitness data that any of these meet our criteria to be considered cheaters. Finally, we highlight future directions for research on conflict in mutualisms, including novel research avenues opened by a relative-fitness-based definition of cheating.
欺骗是共生关系研究中的一个核心概念，大多数研究人员认为欺骗行为既普遍又极具破坏性。然而，目前对欺骗的定义并不能可靠地捕捉到作为欺骗行为研究核心动机的进化威胁。我们描述了欺骗概念的发展，并提炼出一种基于相对适合度的欺骗定义，该定义概括了欺骗行为所带来的进化威胁，即欺骗者将会扩散并侵蚀共生关系的益处。然后，我们描述了为确定欺骗行为正在发生以及更全面地量化适合度冲突而需要进行的实验。接下来，我们讨论我们的定义和方法如何能够实现理论与实验的可比性和整合，目前理论和实验因各自对适合度后果和性状的优先考量而相互割裂。为了评估当前关于欺骗行为的实证证据，我们回顾了关于几种研究得最为充分的共生关系的文献。我们发现，尽管有大量关于低质量伙伴的观察结果，但目前从适合度数据来看，几乎没有证据支持这些伙伴中的任何一个符合我们所定义的欺骗者标准。最后，我们强调了共生关系中冲突研究的未来方向，包括基于相对适合度的欺骗定义所开辟的新研究途径。
