Fitness in invasive social wasps: the role of variation in viral load, immune response and paternity in predicting nest size and reproductive output

Within any one habitat, the relative fitness of organisms in a population can vary substantially. Social insects like the common wasp are among the most successful invasive animals, but show enormous variation in nest size and other fitness-related traits. Some of this variation may be caused by pathogens such as viruses that can have serious consequences in social insects, which range from reduced productivity to colony death. Both individual immune responses and colony-level traits such as genetic diversity are likely to influence effects of pathogen infections on colony fitness. Here we investigate how infections with Kashmir Bee Virus (KBV), immune response and intracolony genetic diversity (due to queen polyandry) affect nest size in the invasive common wasp, Vespula vulgaris. We show that KBV is highly prevalent in wasps and expression of antiviral immune genes is significantly increased with higher viral loads across individuals. Patriline membership within a nest did not influen...在任一栖息地中，种群内生物体的相对适合度会存在显著差异。诸如普通黄胡蜂（common wasp）的社会性昆虫是最为成功的入侵动物类群之一，但其巢群大小及其他与适合度相关的性状却存在极大差异。这类性状差异的部分成因可能是病毒等病原体：这类病原体对社会性昆虫可造成从生产力下降至群体死亡等一系列严重后果。个体免疫反应以及群体层面的性状（如遗传多样性）均可能影响病原体感染对巢群适合度的作用效果。本研究旨在探究克什米尔蜜蜂病毒（Kashmir Bee Virus, KBV）感染、免疫反应以及巢群内遗传多样性（源于蜂王多雄交配，queen polyandry）如何影响入侵物种普通黄胡蜂（Vespula vulgaris）的巢群大小。研究结果表明，KBV在黄胡蜂种群中传播极为广泛，且个体内抗病毒免疫基因的表达量随病毒载量升高而显著上调。巢群内的父系谱系归属并未对...