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Lifetime reproductive success and longevity of workers in a social insect

社会性昆虫工蜂的终生繁殖成功率和寿命

基本信息

批准号：
NE/J013927/1
负责人：
Andrew Bourke
金额：
$ 6.63万
依托单位：
University of East Anglia
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2012
资助国家：
英国
起止时间：
2012 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FJ013927%2F1
关键词：
Lifetime reproductive success longevity workers

项目摘要

The evolution of social behaviour and the evolution of ageing both form major areas of study in evolutionary ecology. The evolution of social behaviour concerns how animal societies such as those of the eusocial insects (ants, bees, wasps and termites) arise and are maintained. The evolution of ageing concerns the factors that affect the longevity of organisms and the pattern of reproduction over their lifetimes. Recently, researchers have realised that these areas are connected, and that orthodox patterns of ageing can be heavily affected by sociality. A key example involves the relationship between lifetime reproductive success (the number of offspring an individual has over its lifetime) and longevity. The standard evolutionary theory of ageing predicts that sources of extrinsic mortality (factors leading to death in the external environment, such as predators, accidents, and so on) select for earlier reproduction, which in turn is paid for by earlier death. This predicts a negative relationship between lifetime reproductive success and longevity, i.e. that individuals producing more offspring have shorter lives. But, in eusocial societies, which contain both breeding and helping individuals, researchers have predicted that the breeders should exhibit a positive relationship between lifetime reproductive success and longevity, i.e. that individuals producing more offspring have longer lives. This is because breeders in eusocial societies are protected against extrinsic mortality by remaining in the nest. The principal investigator's research recently confirmed this prediction by demonstrating for the first time a positive relationship between lifetime reproductive success and longevity in queens of a eusocial insect, the bumble bee Bombus terrestris.In B. terrestris, as in many other eusocial insects, the workers, which are all daughters of the queen, can produce some offspring of their own. Because of the sex determination system in bees, workers' offspring are always males. Reproductive workers will, like queens, be protected from extrinsic mortality if they tend to remain in the nest, but not if they routinely leave the nest to forage. This allows the hypothesized effect of extrinsic mortality to be isolated, because it leads to the prediction that reproductive workers will exhibit a positive relationship between lifetime reproductive success and longevity if they tend to remain in the nest and a negative relationship if they tend to leave the nest to forage. The aim of this project is to test this hypothesis using B. terrestris as the study organism.The project is feasible because B. terrestris is an annual eusocial insect, i.e. one completing its colony cycle in a single season and hence one in which queens and workers live in the colony for at most a few months. B. terrestris colonies are also commercially available and are easy to keep and observe in the laboratory. The lifetime reproductive success and longevity of all mother queens and a sample of their reproductive worker daughters will be determined in a set of colonies whose workers have been individually marked. Birth and death dates, time spent in the nest and lifetime reproductive success will be measured across all individuals, with lifetime reproductive success being measured both as egg-production (measured from filming of nests) and from parentage analyses of males using genetic markers. This research is novel and fundamental because it will test new concepts at the interface of the important areas of social evolution and the evolution of ageing. For this reason, the work will substantially advance our basic understanding of both sociality and ageing in general.

社会行为的进化和衰老的进化都是进化生态学研究的主要领域。社会行为的进化涉及动物社会，如真群居昆虫（蚂蚁、蜜蜂、黄蜂和白蚁）的社会如何产生和维持。衰老的进化涉及影响生物体寿命和其一生中繁殖模式的因素。最近，研究人员已经意识到这些区域是相互联系的，并且传统的衰老模式会受到社会的严重影响。一个关键的例子涉及到终生繁殖成功率（个体一生中生育后代的数量）与寿命之间的关系。标准的衰老进化理论预测，外在死亡的来源（外部环境中导致死亡的因素，如捕食者、事故等）选择了更早的繁殖，而这反过来又以更早的死亡为代价。这预示着终生繁殖成功率与寿命之间的负相关关系，即生育更多后代的个体寿命更短。但是，在包含繁殖和帮助个体的社会中，研究人员预测繁殖者应该在一生的繁殖成功和寿命之间表现出正相关关系，即生育更多后代的个体寿命更长。这是因为在群居社会中，繁殖者通过留在巢中来保护自己免受外来的死亡。首席研究员的研究最近证实了这一预测，首次证明了一种群居昆虫——大黄蜂（bumble bee Bombus terrestris）的蜂王一生的繁殖成功率与寿命之间存在正相关关系。和许多其他的群居昆虫一样，在B. terrestris中，工蜂都是蜂后的女儿，可以产生一些自己的后代。由于蜜蜂的性别决定系统，工蜂的后代总是雄性。如果繁殖工蜂倾向于留在巢中，就会像蚁后一样，免受外来死亡的影响，但如果它们经常离开巢去觅食，就不会。这使得外在死亡率的假设影响被孤立，因为它导致了这样的预测：如果繁殖工蜂倾向于留在巢穴中，它们将表现出终生繁殖成功和寿命之间的正相关关系，如果它们倾向于离开巢穴去觅食，它们将表现出负相关关系。本项目旨在以地芽孢杆菌为研究对象，验证这一假设。这个项目是可行的，因为土蚁是一种一年生的真社会性昆虫，即一种在一个季节完成其群体周期的昆虫，因此蚁后和工蜂最多在群体中生活几个月。地栖菌群也可以在市场上买到，而且很容易在实验室里饲养和观察。在一组工蜂被单独标记的蜂群中，所有母蜂王和它们的生殖工蜂后代的终生繁殖成功率和寿命将被确定。所有个体的出生和死亡日期、在巢中度过的时间和终生生殖成功将被测量，终生生殖成功将通过产蛋量（通过拍摄巢穴来测量）和使用遗传标记对雄性的亲子分析来测量。这项研究是新颖和基础的，因为它将在社会进化和老龄化进化的重要领域的界面上测试新概念。由于这个原因，这项工作将大大提高我们对社会和老龄化的基本理解。