Evolution of Social Immunity and Disease Transfer in Honey Bees

蜜蜂的社会免疫和疾病传播的进化

• 批准号: RGPIN-2019-05679
• 负责人: Betti, Matthew
• 金额: $ 1.17万
• 依托单位: Mount Allison University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=715737
• 关键词: Evolution; Social; Immunity; Disease; Transfer

One unique social behaviour of honey bees is how a colony can mitigate infection of larvae without human interventions. These behaviours, which include grooming and destroying infected larvae, are collectively known as hygienic behaviours in honey bees and more generally referred to as social immunity. In the context of managed or farmed honey bee colonies, this is a desirable trait which could help minimize colony losses and potentially help populations rebound. In the proposed work, I will develop population-level and genetic models which can track the spread of hygienic alleles through a network of colonies. Due to the haploid-diploid nature of honey bee mating, as well as the fact that a queen (the only reproductive female within a colony) can be fertilized by up to 20 males, determining the best practices for breeding programs for hygienic behavior can be complex. Through such modeling it will be possible to determine the conditions in which we can realize a consistent proportion of hygienic bees within colonies that will then be self-sustainable. This analysis can then be used to aid and inform best practices for phenotypic or genotypic breeding programs. Moreover, the developed models can be used to explore the two leading hypotheses on the relationship between social immunity and individual immunity. The first is the Social Group Hypothesis which states that the crowded living conditions of social insects can increase vulnerability to pathogens and thus select for individual immunity, despite high metabolic cost. The Regressive Group Hypothesis states that social immunity will relax selection on individual immune function, and it will be maintained at much lower levels in a population. By developing a competition model between two populations, a mutant which exhibits social immunity and a wild type which maintains high individual immunity due to selection pressure, I will be able to provide insights into the conditions under which each hypothesis may be more beneficial, and which may be more common given present conditions. This model will be able to answer fundamental questions about the consequences of sociability in the Hymenoptera in the context of disease. The long-term objective of this research program is to develop a mathematical framework which can be used to study the effects of relaxed selection on the evolution of a species. The training of undergraduate students with strong interdisciplinary skills is integral to this program.

蜜蜂的一个独特的社会行为是如何在没有人类干预的情况下减轻幼虫的感染。这些行为，包括梳理和消灭受感染的幼虫，统称为蜜蜂的卫生行为，更一般地称为社会免疫。在管理或养殖的蜜蜂群体中，这是一个理想的性状，可以帮助减少群体损失，并可能帮助种群反弹。 在拟议的工作中，我将开发人口水平和遗传模型，可以跟踪卫生等位基因的传播通过网络的殖民地。由于蜜蜂交配的单倍体-二倍体性质，以及女王（殖民地内唯一的生殖雌性）可以由多达20个雄性受精的事实，确定卫生行为育种计划的最佳实践可能是复杂的。通过这样的建模，将有可能确定我们可以在殖民地内实现一致比例的卫生蜜蜂的条件，然后这些蜜蜂将是自我可持续的。然后，该分析可用于帮助和告知表型或基因型育种计划的最佳实践。 此外，开发的模型可以用来探讨社会免疫和个人免疫之间的关系的两个主要假设。第一个是社会群体假说，它指出社会昆虫拥挤的生活条件可以增加对病原体的脆弱性，从而选择个体免疫力，尽管代谢成本很高。回归群体假说指出，社会免疫将放松对个体免疫功能的选择，并且它将在群体中保持在低得多的水平。通过建立两个种群之间的竞争模型，一个突变体表现出社会免疫力，一个野生型由于选择压力而保持高的个体免疫力，我将能够提供对每个假设可能更有益的条件的见解，并且在目前的条件下可能更常见。这个模型将能够回答有关在疾病的背景下，在Hyattera的社会性的后果的基本问题。 该研究计划的长期目标是开发一个数学框架，可用于研究放松选择对物种进化的影响。 培养具有较强跨学科技能的本科生是该计划的组成部分。