Studies of the ecoimmunology of feral organisms can provide valuable insight into how host–pathogen dynamics change as organisms transition from human-managed conditions back into the wild. Honey bees (Apis mellifera Linnaeus) offer an ideal system to investigate these questions as colonies of these social insects often escape management and establish in the wild. While managed honey bee colonies have low probability of survival in the absence of disease treatments, feral colonies commonly survive in the wild, where pathogen pressures are expected to be higher due to the absence of disease treatments. Here, we investigate the role of pathogen infections [Deformed wing virus (DWV), Black queen cell virus (BQCV), and Nosema ceranae] and immune gene expression (defensin-1, hymenoptaecin, pgrp-lc, pgrp-s2, argonaute-2, vago) in the survival of feral and managed honey bee colonies. We surveyed a total of 25 pairs of feral and managed colonies over a 2-year period (2017–2018), recorded overwintering survival, and measured pathogen levels and immune gene expression using quantitative polymerase chain reaction (qPCR). Our results showed that feral colonies had higher levels of DWV but it was variable over time compared to managed colonies. Higher pathogen levels were associated with increased immune gene expression, with feral colonies showing higher expression in five out of the six examined immune genes for at least one sampling period. Further analysis revealed that differential expression of the genes hymenoptaecin and vago increased the odds of overwintering survival in managed and feral colonies. Our results revealed that feral colonies express immune genes at higher levels in response to high pathogen burdens, providing evidence for the role of feralization in altering pathogen landscapes and host immune responses.

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病原体动力学和免疫基因表达在野生蜜蜂存活中的作用

对野生生物生态免疫学的研究可以提供有价值的见解，了解随着生物体从人类管理的条件转变回野外环境，宿主 - 病原体动力学如何变化。蜜蜂（Apis mellifera Linnaeus）提供了一个理想的系统来调查这些问题，因为这些群居昆虫的群体经常逃避管理并在野外建立。虽然在没有疾病治疗的情况下，受管理的蜜蜂群体存活的可能性很低，但野生群体通常在野外生存，由于没有疾病治疗，预计病原体压力会更高。在这里，我们研究了病原体感染 [变形翼病毒 (DWV)、黑皇后细胞病毒 (BQCV) 和 Nosema ceranae] 和免疫基因表达（defensin-1、hymenoptaecin、pgrp-lc、pgrp-s2、argonaute- 2、vago）在野生和受管理的蜜蜂群的生存中。我们在 2 年期间（2017-2018 年）调查了总共 25 对野生和管理菌落，记录了越冬存活率，并使用定量聚合酶链反应 (qPCR) 测量了病原体水平和免疫基因表达。我们的结果表明，野生菌落的 DWV 水平较高，但与受管理的菌落相比，它随时间变化。更高的病原体水平与增加的免疫基因表达相关，野生菌落在至少一个采样周期内在六个检查的免疫基因中的五个中表现出更高的表达。进一步的分析表明，hymenoptaecin 和 vago 基因的差异表达增加了管理和野生菌落越冬存活的几率。