The ecology and evolution of sibling cannibalism in the wild

同类相食是一种几乎所有分类群体都表现出来的行为，它可以分为几个亚型。吃掉自己的兄弟姐妹，即同类相食，是一个有趣的案例，因为它涉及到某种违反直觉的行为，即吃掉与自己有大约50%基因组成相同的亲戚。了解一个物种/个体的同类相食程度的进化和生态原因是一项多方面的任务。同类相食的倾向受到若干具有相反作用的生态因素（如营养效益和疾病成本）的影响。此外，同类相食的倾向可能会受到与食用亲属相关的进化适应性成本的影响。同类相食的程度也可能受到母亲的影响，因为同类相食会降低或提高母亲的进化适应性，这取决于生态环境。因此，兄弟姐妹同类相食可能是兄弟姐妹之间和母亲与子女之间冲突的根源。作为一个复杂而迷人的研究领域，研究同类相食可能有助于进一步发展进化理论（如汉密尔顿规则）的知识，并有利于具有经济（如农业）和保护（入侵物种的研究）重要性的研究。迄今为止，兄弟同类相食的研究受到研究物种多样性低和缺乏基于实地调查的经验数据的限制。创建一个具有更大物种多样性的研究框架可能有助于构建一个更普遍的知识基础，在生态和进化框架中，是什么推动了同类相食的流行。拥有这样一个基地可以让未来对同类相食的研究更有效地进行，更容易做出预测。由于同类相食行为在实验室与自然环境中的表现可能不同，因此有必要在野外增加对同类相食行为的研究，以了解实验室研究如何很好地解释野生种群的行为。本项目旨在进一步了解昆虫同类相食的进化和生态驱动因素，特别是Lygaeidae（一组真正的昆虫，兄弟同类相食的研究很少）和Coccinellidae（瓢虫，一组包含可能由于同类相食而更有效入侵的物种）。实验室的工作最初将集中在测试兄弟姐妹和母亲-后代在同类相食方面的冲突，研究Lygaeids同类相食的全面适应成本的含义（并在此过程中开发研究先前研究不足的群体同类相食的方法），以及母亲在影响Lygaeids和Coccinellids同类相食水平方面的参与。测试母亲参与的工作也可以扩展到考虑同类相食和其他相关特征的遗传性，这是一个以前从进化角度很少关注的主题。田野调查将包括考虑周围食物丰度对Lygaeids和Coccinellidae同类相食水平的影响，并使用分子遗传技术推断昆虫群的亲缘结构。

Cannibalism is a behaviour displayed by nearly all taxonomic groups and it can be divided into several subtypes. The consumption of one's own siblings, sibling cannibalism, presents an interesting case as it entails the somewhat counterintuitive act of eating a relative with whom one shares approximately 50% of its genetic makeup. Understanding the evolutionary and ecological reasons for the degree of sibling cannibalism expressed in a species/individual is a multi-faceted task. Propensity for cannibalism is influenced by several ecological factors (e.g., nutritional benefits and diseases costs) with opposing effects. Additionally, cannibalism propensity can be influenced by the evolutionary fitness costs associated with consuming a relative. Cannibalism levels within a brood may also be influenced by mothers, as within-brood cannibalism can either decrease or increase a mother's evolutionary fitness, depending on the ecological context. Sibling cannibalism can therefore be a source of sibling-sibling and mother-offspring conflict. As well as being a complex and fascinating area of research, studying cannibalism may facilitate further development of knowledge on evolutionary theories such as Hamilton's rule, and can benefit research with economic (e.g., in agriculture) and conservational (in the study of invasive species) importance. To date, research on sibling cannibalism is constrained by the low species diversity of its study species and by its lack of fieldwork-based empirical data. Creating a research framework with greater species diversity may facilitate the construction of a more generalisable knowledge base on what, in an ecological and evolutionary framework, drives cannibalism's prevalence. Possession of such a base could allow future research on cannibalism to progress more effectively, with a greater ease of making predictions. As cannibalistic behaviours may be expressed differently in lab vs. more natural settings it is imperative to increase the amount of work which has been done on cannibalism in the field to see how well laboratory studies can explain the behaviour of wild populations. This project aims to further understand the evolutionary and ecological drivers of sibling cannibalism in insects, specifically in the Lygaeidae (a group of true bugs for whom little sibling cannibalism research has been done) and the Coccinellidae (Ladybirds, a group containing species who may be more efficient invaders due to cannibalism), using a combination of lab and field-based study. Lab work will initially focus on testing ideas of sibling-sibling and mother-offspring conflict over cannibalism, studying the implications of inclusive fitness costs of cannibalism in Lygaeids (and in doing so developing methods to study cannibalism in a previously understudied group) and the involvement of mothers in influencing brood cannibalism levels in both Lygaeids and Coccinellids. The work testing the mother's involvement can also be expanded to consider the heritability of cannibalism and other correlated traits, a subject which has previously garnered little attention from an evolutionary perspective. Fieldwork will include considerations of the influence of surrounding food abundance on cannibalism levels in both Lygaeids and the Coccinellidae, and deduction of the relatedness structure of insect clusters using molecular genetic techniques.