DISSERTATION RESEARCH: Plant sanctions and wasp pollination behaviour in the fig tree - fig wasp mutualism

两个不同物种之间互利的相互作用具有基本的生态重要性。大多数植物和动物都依赖于合作的共生体，但人们对是什么限制共生体变成寄生虫知之甚少。是什么阻止了一方在不付出代价的情况下获得互动的好处？这样的骗子会威胁到互惠互利的关系。最近对互惠系统的研究记录了宿主的制裁，通过降低不合作共生体的适应性来防止作弊。然而，很少有证据表明，制裁足以防止寄生现象在互利共生者中蔓延。这个项目将研究无花果树的制裁和可能的欺骗，他们的授粉无花果黄蜂。无花果树只有在被无花果小蜂授粉后才能产生有活力的种子，而无花果小蜂只有在无花果花中产卵才能繁殖。无花果黄蜂要么携带花粉，要么不携带花粉，无花粉黄蜂在制裁最弱的无花果物种中更常见。调查，操纵现场实验和分子工具将被用来确定是否观察到的主机制裁可以防止无花粉黄蜂在人口中传播。拟议的研究将提供重要的和新颖的信息，广泛适用于互惠系统的进化和维护一般。对互惠关系如何维持的进一步理解，也将有助于我们理解如何防止我们身体和农业系统中的共生体变成寄生虫。

Mutually beneficial interactions between two different species are of fundamental ecological importance. Most plants and animals are dependent on cooperative symbionts, yet it is poorly known what constrains symbionts from turning into parasites. What prevents one partner from reaping the benefits of the interaction without paying the costs? Such cheaters would threaten to break down the mutualism. Recent studies of mutualistic systems have documented host sanctions that might prevent cheating by lowering the fitness of uncooperative symbionts. However, it has rarely been demonstrated that sanctions are sufficient to prevent the spread of parasitism among mutualists. This project will study sanctioning by fig trees and possible cheating by their pollinating fig wasps. Fig trees can produce viable seeds only after being pollinated by fig wasps, and fig wasps can reproduce only by laying their eggs in fig flowers. Fig wasps either do or do not carry pollen, and pollen-free wasps are more common in the fig species with the weakest sanctions. Surveys, manipulative field experiments, and molecular tools will be used to determine whether the observed host sanctions can prevent pollen-free wasps from spreading in a population. The proposed research will provide important and novel information broadly applicable to the evolution and maintenance of mutualistic systems in general. Increased understanding of how mutualisms are maintained will aid our understanding also of how symbionts in our bodies and in agricultural systems can be prevented from turning parasitic.