Genetic and behavioural basis of social organisms-parasite interactions: the case of honeybees and the mite varroa destructor

该项目的目标是产生关于调节影响社会有机体的寄生虫种群的遗传和行为机制的新基本知识。蜜蜂是社会生物的良好典范，因为它们的群体中有大量的个体，它们众所周知的劳动分工，以及操纵它们的环境和研究它们的遗传和行为的技术的存在。灭螨瓦螨是蜜蜂中较新的寄生生物（相互作用不到60年），对新宿主具有较高的致病性。它对蜂群有害影响的可变性是有据可查的，但这种可变性的原因尚未得到很好的理解。已知蜜蜂具有抵抗或耐受螨的行为机制，但这些机制表达的遗传基础以及它们对抑制螨种群增长的相对影响尚不清楚。我们将扩增与数量性状位点相关的DNA标记（我的合作者G.J. Hunt已经对影响蜜蜂行为的基因的cDNA进行了测序，并开发了揭示基因多态性的引物和限制性内切酶组合），这些DNA标记来自于个体工蜂在执行卫生行为(蜜蜂检测、打开细胞、并丢弃被螨虫感染的蜂卵)和梳理行为（工蜂从身体上清除螨虫和/或伤害它们的能力），以确定它们是否影响这些行为特征。我们还将记录遗传对螨繁殖力和螨种群生长率的影响，以及基因型变异、遗传模式和这两种机制的相对影响。此外，我们将进一步研究上述行为与防御行为之间的关系（我们在这方面有初步的数据）。我们对修饰、卫生和防御性状的多效性基因效应感兴趣。我们在蜜蜂和瓦螨的行为和基因研究方面有丰富的经验。因此，本研究成功完成的概率非常高。

The goal of this project is to generate new basic knowledge about the genetic and behavioural mechanisms that regulate the populations of a parasite affecting a social organism. Honeybees are good models of social organisms because of the large number of individuals in their colonies, their well-known division of labour, and the existence of technology to manipulate their environment and to study their genetics and behaviour. The mite Varroa destructor is a relatively new parasite of Apis mellifera (less than 60 years of interaction) and therefore it is generally highly pathogenic to its new host. Variability in its detrimental effects to honeybee colonies is well documented, but the causes of this variability are not yet well understood. It is known that bees posses behavioural mechanisms of resistance or tolerance against the mite, but the genetic basis underlying the expression of these mechanisms, as well as their relative impact on restraining the mite population growth is not well known. We will amplify DNA markers linked to quantitative trait loci (my collaborator G.J. Hunt has sequenced cDNA from genes that influence bee behaviours and developed primers and restriction enzyme combinations that reveal polymorphisms within the genes) from individual workers sampled when performing hygienic behaviour (the ability of bees to detect, open a cell, and discard bee brood infested with mites) and grooming behaviour (the ability of workers to dislodge mites from their bodies and/or injure them), to determine if they influence these behavioural characteristics. We will also document genetic effects on mite fertility and rates of mite population growth, as well as the genotypic variability, mode of inheritance, and relative impact of these two mechanisms. Additionally, we will further study the relationship between the above behaviours and defensive behaviour (we have preliminary data on this regard). We are interested in pleiotropic gene effects for grooming, hygienic, and defensive traits. We have ample experience in behavioural and genetic studies conducted with honeybees and Varroa mites. Therefore, this study has very high probabilities of being completed successfully.