Source and maintenance of recognition cues in ant societies

区分群体成员和非群体成员是一系列关键动物行为的基础，如领地、利他主义和交配。这需要识别信号的变化，但不知道这种变化是如何保持的。无脊椎动物和许多脊椎动物主要使用化学物质来编码关于个体的物种、性别、年龄或种姓的信息，此外还使用警报和踪迹信息素。蚂蚁是世界上最具统治力的动物之一，它们使用特别丰富的化学交流形式，因为它们是社会性的，生活在包含数千万到数百万个体的群体中。蚂蚁是世界上最昂贵的17种害虫中的5种。尽管它们作为有益物种和有害物种都很重要，但人们对它们使用的识别信号知之甚少。事实上，早在100多年前，就有人首次提出蚂蚁识别是基于覆盖在所有昆虫外表面的防水层中存在的化学线索。最近，这一点得到了证实，因为证明了在蚁表面发现的名为角质碳氢化合物的化学物质确实用于识别蚁巢伴侣。我们将利用这一最新知识来研究维持蚂蚁识别信号变异的遗传和环境因素。为了实现这一目标，我们将对蚂蚁Formica exsecta及其几个近亲进行行为、生化、遗传和理论研究。Formica蚂蚁是一个关键的属，有160多个物种，包括著名的土堆建造木蚂蚁，因此是研究最多的昆虫群体之一。因此，已经有了大量的化学、遗传、空间和行为数据，特别是关于F.exsecta的数据，我们正在与之合作的赫尔辛基大学在过去15年里一直在研究这一数据。为了实现我们的主要目标，我们将进行三个平行的研究：1)生化调查，以跟踪关键角质碳氢化合物(CHC)的产生、运输和最终分泌。这将使我们了解个体气味是如何以及在哪里产生的。2)一项研究，其目的是剖析蚊虫和其他蚁类物种所使用的CHC(气味)的遗传和环境成分的可变性。这将使用最新的分子工具来实现。我们将第一次在一个种群内为100多个群体构建一棵家谱，以计算出化学线索的遗传性。然后，我们将制作一张遗传图谱，允许涉及关键碳氢化合物生产的基因进行本地化。我们将使用蜜蜂和果蝇的基因组来测试候选基因的作用，并测试在这些基因上平衡选择的证据。3)最后，使用基于主体的模型，我们将从理论上研究识别线索变异(在个体、群体、物种水平)在可能受到不同条件影响的空间环境中的进化和维持。我们将使用我们的经验数据来避免以前与系统过度简化相关的问题。除了处于迅速崛起的化学生态学领域的前沿，这项研究还在英国昆虫保护的两个关键领域提供了帮助。首先，在英国，F.exsecta是1类受威胁物种，因此我们将提供重要的信息和专业知识来支持该物种的保护。其次，了解环境力量与遗传变异是如何相互作用的，将为识别系统的进化和维持提供新的见解，不仅在蚂蚁中，而且在许多昆虫物种中，因为我们正在研究的化学物质几乎是由所有无脊椎动物合成的。

Distinguishing group members from non-group members underlies a vast array of key animal behaviours, such as territoriality, altruism and mating. This requires variation in recognition signals but it is not known how this variation is maintained. Invertebrates, and many vertebrates, primarily use chemicals to encode information about an individual's species, sex, age or caste, in addition to alarm and trail pheromones. Ants are among the most dominant animals in the world and employ particularly rich forms of chemical communication since they are social, living in colonies containing tens to millions of individuals. Ants comprise five of the world's top seventeen most costly pest insects. Despite their importance as both beneficial and pest species, there is little knowledge about the recognition signals they employ. In fact, it was over 100 yrs ago that it was first suggested that ant recognition was based on chemical cues present in the waterproof layer that coats the outer surface of all insects. Very recently this has been confirmed by demonstrating that chemicals known as cuticular hydrocarbons found on the surface of Formica ants are indeed used in nest mate recognition. We will exploit this recent knowledge to study the genetic and environmental forces that underpin the maintenance of variation in ant recognition signals. To achieve this, we will conduct behavioural, biochemical, genetic and theoretical studies on the ant Formica exsecta and several of its close relatives. Formica ants are a keystone ant genus, comprising over 160 species, including the well-known mound-building wood ants and thus are one of the best studied groups of insects. Therefore, there is already a vast wealth of chemical, genetic, spatial and behavioural data, especially for F. exsecta, which has being studied over the past 15 years by Helsinki University with whom we are collaborating. To achieve our main aim we will conduct three parallel studies: 1) A biochemical investigation to track the production, transportation and eventual secretion of the key cuticular hydrocarbons (CHC) in F. exsecta. This will allow us to understand how and where an individual odour develops. 2) A study aimed at dissecting the genetic and environmental components of variability of the CHC (odour) used by F. exsecta and other Formica species. This will be achieved using the latest molecular tools. For the first time, we will construct a family tree within a single population for over 100 colonies to work out the heritability of the chemical cues. We will then produce a genetic map which will allow the genes that are involved in the production of the key hydrocarbons to be localised. We will test the role of candidate genes, using the genomes of the honeybee and Drosophila, and test for evidence of balancing selection on these genes. 3) Finally, using agent-based modelling we will investigate theoretically the evolution and maintenance of recognition cue variation (at individual, colony, species levels), within a spatial environment that can be subject to different conditions. We will use our empirical data to avoid previous problems associated with over-simplification of the system. In addition to being at the forefront of the rapidly emerging field of chemical ecology, this study helps in two key areas of UK insect conservation. Firstly, in the UK, F. exsecta is a Category 1 threatened species, so we will provide vital information and expertise to underpin the species' conservation. Secondly, understanding how environmental forces interact with genetic variation will provide new insights into the evolution and maintaince of recognition systems not only in ants but in many species of insects since the chemicals we are investigating are synthesised by almost all invertebrates.