Data from: Genetic diversity confers colony-level benefits due to individual immunity

Several costs and benefits arise as a consequence of eusociality and group-living. With increasing group size, spread of disease among nest-mates poses selective pressure on both individual immunity and group-level mechanisms of disease resistance (social immunity). Another factor known to influence colony-level expression of disease is intracolony genetic diversity, which in honeybees (Apis mellifera) is a direct function of the number of mates of the queen. Colonies headed by queens with higher mating numbers have less variable infections of decreased intensity, though the underlying mechanisms remain unclear. By pathogen-challenging larvae in vitro, we decoupled larval immune response from mechanisms of social immunity. Our results show that baseline immunity and degree of immune response do not vary with genetic diversity. However, intracolony variance in antimicrobial peptide production after pathogen challenge decreases with increasing genetic diversity. This reduction in variability of the larval immune response could drive the mitigation of disease observed in genetically diverse colonies.

真社会性 (eusociality) 与群体生活模式会催生一系列成本与收益。随着群体规模扩大，巢友间的疾病传播会对个体免疫及群体层面的疾病防御机制，即社会免疫 (social immunity)，产生选择压力。另一个已知会影响蜂群层面疾病表现的因素是蜂群内遗传多样性；在西方蜜蜂（Apis mellifera）中，这一多样性直接取决于蜂王的交配次数。由交配次数更多的蜂王统领的蜂群，其感染强度更低且感染变异程度更小，但其背后的调控机制仍未明确。本研究通过体外对幼虫进行病原体攻击实验，将幼虫免疫反应与社会免疫机制分离开来。研究结果显示，幼虫的基础免疫水平与免疫反应强度均不随遗传多样性发生变化。但在病原体攻击后，蜂群内幼虫抗菌肽 (antimicrobial peptide) 的产生量变异程度会随遗传多样性提升而降低。幼虫免疫反应变异程度的这一降低，或可促成遗传多样性更高的蜂群中所观察到的疾病缓解效应。