ROLE SPECIALIZATION AND PLASTICITY AT THE ORIGIN OF EUSOCIALITY

欧洲社会性起源的角色专业化和可塑性

• 批准号: NE/X014770/1
• 负责人: Jeremy Field
• 金额: $ 68.13万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX014770%2F1
• 关键词: ROLE; SPECIALIZATION; PLASTICITY; ORIGIN; EUSOCIALITY

The evolution of eusociality, where some individuals forfeit their own reproduction to help others, represents one of the major evolutionary transitions. The fundamental feature of eusociality is the division of labour: queens are specialist egg-layers while workers specialize on tasks such as foraging. Numerous factors that could favour helping have been identified, and its evolution can appear deceptively simple. For example, the fact that females are as closely related to their siblings as to their own offspring might suggest that just a tiny advantage over independent nesting will be enough to promote the evolution of helping. However, this implies that there was extensive pre-existing plasticity at the origin of eusociality, allowing individuals to take on roles similar to today's queens and workers. In the often-imagined scenario where a mutant offspring takes over brood provisioning, ceding egg-laying rights to a mother 'queen', the offspring could have to provision at twice the rate of an independent breeder, and the mother could have to lay twice as many eggs, to avoid selection on daughters favouring the ancestral strategy. This might be achieved if specialization frees up resources no longer utilized in performing one role, but only if there is a highly efficient trade-off between functions. A key unanswered question is therefore how efficient division of labour would be when it first evolved. Efficiency also requires tolerance and responsiveness: would ancestral females accept provisions provided by helpers, and would they adjust their own feeding effort accordingly?The payoff through specialization could be condition-dependent. A long-standing hypothesis is that the first helpers were small females with low reproductive value that forfeited little by helping a fully fertile relative. However, the extent to which payoffs to ancestral females from providing or receiving help depend on phenotype remains unclear. Furthermore, a critical untested assumption of the subfertility hypothesis concerns the foraging ability of small/subfertile females. Such females may have low fecundity when nesting independently, but the subfertility hypothesis assumes that they will perform better with helper tasks such as provisioning. Key objectives are to use large-scale field manipulations of the well studied non-social wasp Ammophila pubescens to for the first time: (1) Test the benefits of role specialization: to what extent can non-social females increase their lifetime egg-laying or provisioning when forced experimentally to specialize? (2) Test a key assumption of the subfertility hypothesis: do small females have the most to gain through specializing as provisioners? (3) Test whether there are complementary phenotype combinations where both parties could gain by nesting together (4) Test the tolerance and responsiveness of non-social females to received help The overall result will be a new and exciting perspective on how trade-offs and plasticity could influence or constrain the origin of eusociality, with important implications for the magnitude of ecological and genetic advantages necessary for eusociality to be favoured by selection.The work will benefit the international community of researchers in a variety of disciplines such as entomology, evolutionary biology, behavioural ecology and animal behaviour, including both theoreticians and empiricists, as well as those working specifically on social evolution and the evolution of animal societies. The specific research focus has been little studied, so that there is potential for a significant advancement of knowledge, in terms of both the novel approach and the new data that will be generated. There are interesting parallels between the division of labour in social insects and other taxa such as bacteria and algae.

社会性的进化，即一些个体为了帮助他人而放弃自己的繁殖，代表了主要的进化转变之一。群居性的基本特征是劳动分工：蜂王是专门产卵的，而工蜂则专门从事觅食等任务。已经确定了许多有利于帮助的因素，它的演变可能看起来很简单。例如，雌性与兄弟姐妹的亲缘关系就像与自己的后代的亲缘关系一样密切，这一事实可能表明，相对于独立筑巢而言，仅仅一个微小的优势就足以促进互助的进化。然而，这意味着在群居起源时存在广泛的预先存在的可塑性，允许个人承担类似于今天的女王和工人的角色。在人们经常想象的场景中，一个突变的后代接管了后代的供应，把产卵权让给了母亲“女王”，后代的供应率可能是独立繁殖者的两倍，母亲可能不得不产下两倍的鸡蛋，以避免女儿选择更倾向于祖先的策略。如果专门化释放了不再用于执行一个角色的资源，但只有在功能之间存在高效权衡的情况下才能实现这一点。因此，一个悬而未决的关键问题是，劳动分工最初演变时的效率有多高。效率还需要容忍和反应：雌性祖先会接受帮手提供的食物吗？她们会相应地调整自己的喂养努力吗？专业化的回报可能取决于条件。一个长期存在的假设是，第一批帮助者是生殖价值较低的小雌性，帮助一个完全有生育能力的亲属，对她们没有什么损失。然而，提供或接受帮助对祖先女性的回报取决于表型的程度仍不清楚。此外，低生育能力假说的一个关键的未经检验的假设涉及到小/低生育能力的雌性的觅食能力。这样的雌性在独立筑巢时繁殖力可能较低，但低繁殖力假说认为，它们在提供食物等辅助任务中会表现得更好。本文的主要目的是首次对已被充分研究的非社会性黄蜂进行大规模的野外操作，以验证角色专业化的好处：当实验性地强迫非社会性黄蜂专业化时，非社会性黄蜂在多大程度上可以增加其一生的产卵或供应？(2)检验低生育能力假说的一个关键假设：矮小的雌性通过专门提供食物获得的收益最大吗？(3)测试是否存在互补的表型组合，双方都可以通过一起筑巢获得好处(4)测试非社会性雌性对接受帮助的耐受性和反应性。总体结果将为权衡和可塑性如何影响或限制群居性的起源提供一个新的和令人兴奋的视角，对群居性在选择中得到青睐所必需的生态和遗传优势的大小具有重要意义。这项工作将使昆虫学、进化生物学、行为生态学和动物行为学等各个学科的国际研究人员受益，包括理论家和经验主义者，以及那些专门研究社会进化和动物社会进化的研究人员。具体的研究重点很少被研究，因此就新方法和将产生的新数据而言，有可能在知识方面取得重大进展。群居昆虫的劳动分工与其他类群（如细菌和藻类）之间有一些有趣的相似之处。