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）与集群生活所带来的演化后果兼具多重成本与收益。随着种群规模扩大，巢友间的疾病传播会对个体免疫与群体层面的疾病抵抗机制（社会免疫，social immunity）施加选择压力。另一个已知会影响蜂群疾病表现的因素是蜂群内遗传多样性，而在西方蜜蜂（Apis mellifera）中，该多样性直接取决于蜂王的交配次数。由交配次数较多的蜂王统领的蜂群，其感染程度更低且感染状态的变异程度更小，尽管背后的调控机制尚不明晰。本研究通过体外病原体胁迫幼虫的实验，将幼虫的免疫反应与社会免疫机制分离开来。实验结果显示，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。不过，在病原体胁迫后，蜂群内抗菌肽（antimicrobial peptide）产生量的群体内变异程度会随遗传多样性的提升而降低。这种幼虫免疫反应变异程度的降低，或许可以解释遗传多样性更高的蜂群中所观测到的疾病缓解现象。