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.

真社会性的进化，即一些个体放弃自己的繁殖来帮助他人，代表了主要的进化转变之一。真社会性的基本特征是劳动分工：蜂王是产蛋专家，而工蜂则专门从事觅食等任务。已经确定了许多可能有利于帮助的因素，而且其演变可能看似简单。例如，雌性与兄弟姐妹的关系就像与自己的后代一样密切，这一事实可能表明，相对于独立筑巢的微小优势就足以促进帮助的进化。然而，这意味着在真社会性的起源中存在着广泛的可塑性，使得个体能够扮演类似于今天的蚁后和工蚁的角色。在人们经常想象的场景中，突变后代接管了育雏供应，将产卵权让给了母亲“女王”，后代可能必须以独立饲养者两倍的速度提供食物，而母亲可能必须产下两次尽可能多的鸡蛋，以避免选择有利于祖先策略的女儿。如果专业化能够释放不再用于执行某一角色的资源，那么这一目标就可以实现，但前提是职能之间存在高效的权衡。因此，一个尚未解答的关键问题是，劳动分工在最初发展时的效率如何。效率还需要宽容和反应能力：祖先女性会接受助手提供的食物吗？它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低的体型较小的雌性，它们在帮助完全有生育能力的亲戚时几乎没有损失什么。然而，女性祖先提供或接受帮助的回报在多大程度上取决于表型仍不清楚。此外，生育力低下假说的一个未经检验的关键假设涉及体型较小/生育力低下的雌性的觅食能力。这些雌性在独立筑巢时的繁殖力可能较低，但繁殖力低下的假说认为，它们在提供食物等辅助任务时会表现得更好。 主要目标是首次对经过深入研究的非社会性黄蜂 Ammophila pubescens 进行大规模现场操作：（1）测试角色专门化的好处：非社会性雌性在多大程度上可以增加其一生的产卵量或者在被迫实验性专业化时进行配置？ (2) 检验生育力低下假说的一个关键假设：体型较小的女性通过专业化作为供给者是否能获得最大收益？ (3) 测试是否存在互补的表型组合，双方可以通过筑巢而获益 (4) 测试非社会女性对接受帮助的耐受性和反应性 总体结果将是一个新的、令人兴奋的视角，关于如何权衡和可塑性可能会影响或限制真社会性的起源，对真社会性通过选择所必需的生态和遗传优势的大小具有重要影响。这项工作将使国际社会各个学科的研究人员受益，例如昆虫学、进化生物学、行为生态学和动物行为，包括理论家和经验主义者，以及专门研究社会进化和动物社会进化的学者。具体的研究重点很少被研究，因此在新方法和将产生的新数据方面，知识有可能取得重大进展。群居昆虫与细菌和藻类等其他类群的分工之间存在有趣的相似之处。