QUEEN-WORKER COADAPTATION AND CONFLICT IN A PRIMITIVELY EUSOCIAL BEE

理解家庭内部发生的利益冲突一直是进化生物学研究的一个主要焦点：除非他们在基因上是相同的，否则每个家庭成员的确切进化利益往往是不同的。在社会性昆虫中，家庭冲突的研究尤其深入，在这些昆虫中，蜂王和她的工蜂之间存在潜在的冲突，比如谁应该产卵，后代的性别比例是多少，以及蜂王的任期长短。然而，虽然现在对这些冲突的进化终点有了很多了解，但对潜在的遗传结构和蜂王和工蜂表达基因之间的相互适应模式知之甚少。这项建议将调查英国社会汗蜂Lasioglossum malachurum（膜翅目：Halictidae）的女王工作者的相互作用。一个关键的方法将是交叉培养：就在工蜂成年之前，蚁后将在巢穴之间转换。因为交叉寄养的蚁后不再与基因相关的工蚁共用一个巢穴（通常是它们自己的后代），交叉培育意味着（1）蜂王和工蜂对后代特征的影响可以分开;（2）蚁后与其工蚁行为之间的任何后续关联（现在在不同的巢穴中）必须反映工蜂从蚁后那里继承的基因，而不是共同环境的影响;（3）蚁后和工蚁特征之间的“错配”产生了--这种错配在持续的进化冲突中是可以预期的，但通常无法进行研究，因为进化在很大程度上消除了它们。及DNA指纹分析，以确定每只后代是由蚁后或工蜂所产，这项工作将达致以下目的：测试进化是否导致了蚁后在与新巢中的工蚁的生殖冲突中获胜的能力之间的相关性，以及她的工蜂在与一个无关的蚁后的冲突中获胜的能力。目标二：进行第一次直接测试，以确定蚁后是否会出于自身利益而操纵工蜂的体型和数量，例如，通过减小工蜂的体型，从而降低工蜂与蚁后争夺后代的能力。目标3：将蚁后对体型（一个关键的后代性状）的影响与工蜂的影响分开，并从理论上研究潜在的遗传结构。进行第一次直接测试的一个关键假设的进化帮助在Hyattera：假设一个更大的工人群体导致更多的女性偏见的性别比例的后代。由于工蜂与蚁后的雌性后代的关系比与雄性后代的关系更密切，这种效应可能有助于帮助。该研究系统允许在自然选择发挥作用的实地获得异常大的样本量。总体结果将是迄今为止对蚁后-工蚁共同进化过程最全面的理解，包括对几个关键假设的首次检验。实证工作将在苏塞克斯大学进行，该项目将与项目合作伙伴Mathias Köliker教授（瑞士巴塞尔大学）合作。

Understanding the conflicts of interest that occur within families has been a major focus of research in evolutionary biology: unless they are genetically identical, the precise evolutionary interests of individual family members often differ. Family conflicts have been particularly well studied in social insects, where there is potential conflict between the queen and her workers over questions such as who should lay the eggs, what sex-ratio of offspring to produce, and the length of tenure of the queen. However, while much is now known about the evolutionary endpoint of these conflicts, little is known about the underlying genetic architecture and the pattern of reciprocal adaptation between queen- and worker-expressed genes. This proposal will investigate queen-worker interactions in the UK social sweat bee Lasioglossum malachurum (Hymenoptera: Halictidae). A key method will be cross-fostering: just before workers reach adulthood, queens will be switched between nests. Because cross-fostered queens no longer share a nest with genetically related workers (which would normally be their own offspring), cross-fostering means that (1) queen and worker influences on offspring characteristics can be separated; (2) any subsequent correlations between the behaviour of a queen and her workers (now in separate nests) must reflect genes inherited by workers from queens rather than effects of the common environment; (3) 'mismatches' between queen and worker characteristics are generated - mismatches of the kind expected during on-going evolutionary conflict, but not normally available to study because evolution has largely eliminated them.By using a combination of cross-fostering, and DNA fingerprinting to determine whether each offspring was produced by queen or workers, the work will achieve the following objectives.Objective 1: Test whether evolution has led to a correlation between a queen's ability to prevail in reproductive conflicts with the workers in her new nest, and the ability of her workers to prevail in the same conflicts with an unrelated queen. Objective 2: Carry out the first direct test of whether queens normally manipulate worker size and number in their own interests, for example by reducing worker size and therefore a worker's ability to compete with the queen over offspring production.Objective 3: Separate queen influences from worker influences on body size, a key offspring trait, and investigate the underlying genetic architecture theoretically.Objective 4: Carry out the first direct test of a key hypothesis for the evolution of helping in Hymenoptera: the hypothesis that a larger group of workers leads to a more female-biased sex-ratio of offspring. Because workers are more closely related to female- than male offspring of the queen, such an effect could facilitate helping. The study system allows exceptionally large sample sizes to be obtained in the field, where natural selection operates. The overall result will be the most comprehensive understanding to date of the process of queen-worker coevolution, including the first tests of several key hypotheses. Empirical work will be carried out at the University of Sussex, and the project will involve collaboration with Project Partner Prof Mathias Kölliker (University of Basel, Switzerland).