Interactions between learning and non-learning plasticity in the beadlet sea anenome Actinia equina: A multidimensional reaction norm approach.

学习能力在动物中广泛存在，并且被认为是进化出来的，因为它使它们能够根据新信息改变自己的行为方式。例如，当动物遇到一个新的事件时，它通常会通过躲藏来回应。但是，如果该事件经历了多次，结果证明并不危险，动物就会逐渐减少它躲藏的时间，每次遇到相同的事件。这种简单的学习形式被称为习惯化，习惯化的好处是它减少了不必要的躲藏时间。相反，这段时间可以用于其他重要的活动，比如寻找食物或配偶。虽然在许多物种中都有很好的习惯化记录，但我们对这一过程及其进化原因的认识仍然存在重大差距。首先，动物在没有学习的情况下也会调整自己的行为，例如，如果有捕食者等威胁出现，它们会躲得更久。这些类型的变化被称为行为可塑性。目前，对于非习得性可塑性如何影响习得性学习还知之甚少。我们认为可塑性会影响学习，因为两者都依赖于动物处理外部条件信息的能力。例如，如果存在额外的风险，比如捕食者，习惯化可能会发生得更慢（在重复暴露于无害的刺激时，隐藏时间的下降速度会更慢）。同样，当从躲藏中走出来的奖励（比如食物的出现）更高时，习惯化可能会更快发生。此外，由于“遗忘”的过程，当重复刺激之间的间隔较长时，习惯化可能不太可能发生。有趣的是，遗忘可能和学习一样有益，因为它可以防止在缺乏相关信息的情况下形成习惯。我们的第一个目标是了解习惯是如何受到风险、回报和学习机会时机的影响的。其次，众所周知，个体的行为不同，包括他们的学习模式（例如，他们习惯的速度有多快），但我们不知道他们在习惯如何受到上述附加条件的影响方面是否存在差异。在这里，我们将测试这些差异，如果存在，确定这些差异中有多大比例可以用遗传变异来解释。如果在个体和基因型之间存在学习模式的差异（以及它如何受到附加条件的影响），这将表明学习可以服从于自然选择的进化。我们将在海葵中研究这些问题，海葵是刺胞动物门的一员，该门还包括水母和珊瑚。研究这些动物的隐藏行为很容易，因为当它们受到身体上的干扰时（在这种情况下是用喷水），它们会缩回觅食的触角，这种隐藏反应的持续时间可以被反复刺激，并通过人工智能系统分析视频片段来自动测量。刺胞动物也是一个重要的动物群体，因为它们在生命进化树上与脊椎动物、昆虫和软体动物等更复杂的“双侧”物种处于同一水平。因此，刺胞动物的任何学习模式都可能是古老的，它们独立于更复杂动物的中枢神经系统进化而来。此外，关于这些简单动物的学习能力的见解可以应用于更复杂和圈养物种的研究，我们希望设计出优化动物福利和生产习惯的条件。总之，我们将研究影响海葵习惯化的条件，以深入了解学习的进化，并提供实用的知识，然后可以适应研究和操纵更复杂动物的学习。

Learning is widespread in animals and is thought to have evolved because it enables them to change the way they behave on the basis of new information. For example, when an animal encounters a new event it will often respond by hiding. But if that event is experienced multiple times and turns out not to be dangerous, the animal will gradually reduce the amount of time it hides for, each time the same event is encountered. This simple form of learning is called habituation and the benefit of habituating is that it reduces the amount of time spent hiding needlessly. Instead, that time can be used for other important activities such as searching for food or mates. While habituation has been well documented in an array of species, important gaps in our knowledge of this process, and its evolutionary causes, remain. First, animals also adjust their behaviour in the absence of learning, for example by hiding for longer if a threat like a predator is present. These types of changes are known as behavioural plasticity. At present, little is known about how learning to habituate could be affected by non-learned plasticity. We would expect plasticity to affect learning because both are dependent on an animal's ability to process information about external conditions. For instance, habituation might occur more slowly (a slower decline in hiding times across repeated exposures to a stimulus that turns out to be non-harmful) if additional risks such as a predator are also present. Equally, habituation might occur more rapidly when the rewards of emerging from hiding, such as the presence of food, are higher. Additionally, habituation might be less likely when the intervals between repeated stimulation are longer, due to the process of 'forgetting'. Interestingly, forgetting might be as beneficial as learning because it would prevent habituation in the absence of relevant information. Our first objective is to understand how habituation is affected by risk, reward and the timing of learning opportunities. Second, it is known that individuals differ in their behaviour including in their pattern of learning (e.g. how quickly they habituate) but we do not know if they differ in how habituation is affected by additional conditions such as those discussed above. Here, we will test for such differences and, where present, determine what proportion of those differences can be explained by genetic variation. If differences in learning pattern (and how it is affected by additional conditions) are present, between individuals and genotypes, this would show that learning can be subject to evolution by natural selection. We will investigate these questions in a sea anemone, a member of the cnidarian phylum, which also includes jellyfish and corals. Hiding behaviour is easy to study in these animals because they retract their feeding tentacles when physically disturbed (in this case using a water jet), and the duration of this hiding response can be repeatedly stimulated and automatically measured using an artificial intelligence system to analyse video footage. Cnidarians are also an important group of animals as they occupy the same level in the evolutionary tree of life as more complex 'bilateral' species such as vertebrates, insects and molluscs. Therefore, any patterns of learning present in cnidarians could be ancient, having evolved independently of the central nervous systems seen in more complex animals. Furthermore, the insights about learning in these simple animals could then be applied to studies of more complex and captive species where we want to devise conditions that optimise habituation for reasons of animal welfare and production. In summary, we will study the conditions that affect habituation in sea anemones to gain insights into the evolution of learning and provide practical knowledge that can then be adapted to study and manipulate learning in more complex animals.