PUBLIC GOODS AND SOCIALLY RESPONSIVE FEMALES

解释动物为什么以及如何相互合作仍然是一个有趣的挑战。我们知道，家庭中的个人或经常相互交往的人更有可能从相互合作中获得互惠利益。然而，在动物王国中有很多例子，这些条件并不成立，在无法预测的情况下观察到合作。我们最近在研究果蝇的社会反应时发现了这样一个例子。它们不生活在家庭或社会群体中，这预示着它们不太可能表现出社会合作行为。然而，我们发现女性对社会环境的反应非常微妙。例如，当它们发现有其他雌性存在时，它们会迅速提高产卵率，改变它们的性接受度。在食物基质上相遇的一群雌虫产下的卵和其他雌虫产下的卵聚集在一起，出乎意料的是，这些卵似乎受益于其他雌虫卵提供的合作保护。集体产卵似乎是有益的，因为鸡蛋有一层抗菌和抗同类的“涂层”：这种涂层可以扩散并防止产卵的基质变质，并防止鸡蛋被存在的任何幼虫吃掉。这种防御涂层保护了食物斑块上的成批卵（以及由此产生的幼虫）。然而，这些抗微生物和抗食人化学物质的生产在能量上是昂贵的，并且可能被其他人开发利用。这是因为，如果一些个体将“无防御”的卵产在那些具有强大抗菌外壳或有效抗同类相食防御的卵旁边，它们就可以在不支付成本的情况下受益，因此可以“搭便车”。是什么阻止了大多数人这样的欺骗行为，这个问题的解释存在于一个强大的关于“公共物品”的理论体系中。这一解释的关键在于，生产公共产品（即抗菌剂和反同类相食防御措施）的好处是否“非线性”，例如，如果每个人都能从中受益的唯一途径是有一定数量的合作个体参与进来。我们项目的目的是衡量在我们的测试系统中，公共产品的合作是如何以及为什么发生的，从而测试这一重要理论的预测。利用果蝇系统的力量，我们可以通过实验操纵整个系统，从感官输入，到公共产品本身的生产，再到雌性个体的繁殖产出。我们将研究：(1)通过生产抗菌和防同类相食化学品等公共产品来响应社会环境对女性的好处的性质。(2)公共物品生产与健康关系的形成。(3)社会响应性公共产品生产的基因调控机制。这个项目的结果将为我们理解社会生物学的基本组成部分提供重要的一步。这些原则将对整个分类群产生广泛的影响，并将帮助我们了解我们的行为方式和原因。

Why and how animals cooperate with each other remains a fascinating challenge to explain. We know that individuals within families or that regularly interact with each other are far more likely to gain reciprocal benefits from cooperating with each other. However, there are many examples across the animal kingdom where these conditions don't hold and where cooperation is observed in situations in which it isn't predicted. We have recently uncovered such an example in our studies of the social responses of fruitflies. They don't live in familial or social groups, which predicts that they should be very unlikely to express socially cooperative behaviour. Nevertheless, we have found that females have remarkably fine-tuned responses to their social environments. For example, when they detect the presence of other females they very rapidly increase their rate of egg laying and alter their sexual receptivity. Eggs laid by groups of females that meet on food substrates females are laid together in clumps together with those of other females and, unexpectedly, these eggs seem to benefit from the cooperative protection offered by the eggs of other females.Laying eggs in communal batches seems to be beneficial because eggs are laid with an antimicrobial and anticannibalism 'coating': this diffuses and prevents spoilage of the substrate on which the eggs are laid, and prevents eggs from being eaten by any larvae that are present. The defensive coating protects batches of eggs (and resulting larvae) on a food patch. However, the production of these antimicrobial and anticannibalistic chemicals is energetically costly and potentially open to exploitation by others. This is because, if some individuals lay 'defenceless' eggs next to those with a strong antimicrobial coat or with effective anti-cannibalism defences, they can benefit without paying costs and hence can 'free-ride' the system. The explanation for what prevents most individuals from cheating like this resides in a powerful body of theory concerning 'public goods'. Key to the explanation is whether the benefits of producing public goods (i.e. the antimicrobial and anti-cannibalism defences) are 'non linear', for example if the only way everyone can benefit is if a threshold number of cooperating individuals pitch in. The aim of our project is to measure how and why cooperation over public goods occurs in our test system, and hence test the predictions of this important theory. Using the power of the fruitfly system, we can do this by experimentally manipulating the whole system, from the sensory inputs, to the production of public goods themselves, to the outcome in terms of the reproductive output of individual females.We will investigate:(1) The nature of benefits to females from responding to social environments through the production of public goods such as antimicrobial and anti-cannibalistic chemicals. (2) The shape of the relationship between the production of public goods and fitness.(3) The gene regulatory mechanisms underlying the production of socially responsive public goods.The results of this programme will provide a significant step forward in our understanding of fundamental components of social biology. These principles will have broad impact across taxa and will help to show us how and why we behave as we do.