Evans Jay D, Pettis Jeffery S
United States Department of Agriculture, Agricultural Research Service, Bee Research Laboratory, Beltsville, Maryland 20705, USA.
Evolution. 2005 Oct;59(10):2270-4. doi: 10.1111/j.0014-3820.2005.tb00935.x.
Social insects have evolved both communal and individual traits that reduce the impacts of their numerous parasites and pathogens. Among the individual traits, innate-immune responses have the potential to reduce both individual mortality and the spread of pathogens among colony members. An understanding of the costs and benefits of such responses can provide a more complete understanding of a primary risk of social life, horizontal disease transmission among colony members. Here we assess the impacts of individual immunity on colony-level disease in honey bee (Apis mellifera) colonies following exposure to an important bacterial pathogen (Paenibacillus larvae subsp. larvae, cause of the disease American foulbrood). Colony-level disease rates were negatively correlated with the immune responsiveness of colony members, as assessed by larval transcript levels for the gene encoding the antibacterial peptide abaecin. Concomitantly, colonies whose members mounted a stronger abaecin response showed significantly lower productivity, indicating a colony-level cost to this immune response. The results show considerable variation across colonies in an immune trait important for survival, and point toward a significant trade-off between this trait and colony productivity.
社会性昆虫进化出了群体和个体特征，以降低众多寄生虫和病原体对它们的影响。在个体特征中，先天免疫反应有可能降低个体死亡率以及病原体在群体成员之间的传播。了解这种反应的成本和收益，可以更全面地理解社会生活的一个主要风险，即病原体在群体成员之间的水平传播。在此，我们评估了蜜蜂（西方蜜蜂）群体在接触一种重要的细菌病原体（幼虫芽孢杆菌幼虫亚种，美洲幼虫腐臭病的病原体）后，个体免疫对群体层面疾病的影响。通过编码抗菌肽 abaecin 的基因的幼虫转录水平评估，群体层面的疾病发生率与群体成员的免疫反应性呈负相关。与此同时，其成员对 abaecin 反应更强的蜂群显示出显著更低的生产力，这表明这种免疫反应在群体层面存在成本。结果表明，在对生存至关重要的免疫特征方面，不同蜂群存在相当大的差异，并表明该特征与群体生产力之间存在重大权衡。
