Varroa destructor feeds primarily on honey bee fat body tissue and not hemolymph
Varroa destructor feeds primarily on honey bee fat body tissue and not hemolymph
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DOI：
10.1073/pnas.1818371116
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发表时间：
2019-01-29
影响因子：
11.1
通讯作者：
vanEngelsdorp, Dennis
中科院分区：
文献类型：
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作者：
Ramsey, Samuel D.;Ochoa, Ronald;vanEngelsdorp, Dennis
寄生螨狄斯瓦螨是全球蜜蜂健康下降的最大单一驱动因素。更好地了解这种寄生虫及其宿主的关联对于制定可持续管理实践至关重要。我们的工作表明，这种寄生虫并不像公认的观点那样消耗血淋巴，而是通过消耗脂肪体（一种大致类似于哺乳动物肝脏的组织）来损害宿主蜜蜂。用荧光生物素标记蜜蜂血淋巴和脂肪体。允许以这些蜜蜂为食的螨的肠道中的荧光分布与宿主蜜蜂的血淋巴的荧光分布非常不同，但始终与脂肪体特有的荧光分布相匹配。通过透射电镜观察，我们观察了被寄生的蜜蜂伤口的外部消化脂肪体组织。然后给处于生殖阶段的螨喂食由一种或两种组织组成的饮食。螨喂养血淋巴显示健身指标没有什么不同的饥饿控制。与血淋巴相比，脂肪体喂养的螨存活时间更长，产卵量更多，表明脂肪体也是其食物的组成部分。总的来说，这些发现强烈表明瓦螨属正在利用脂肪体作为其主要的营养来源：一种对健康蜜蜂的适当免疫功能、杀虫剂解毒、越冬生存和其他几个基本过程不可或缺的组织。这些发现强调了重新审视我们对这种寄生虫及其对蜜蜂健康的直接和间接影响的理解的必要性。
The parasitic mite Varroa destructor is the greatest single driver of the global honey bee health decline. Better understanding of the association of this parasite and its host is critical to developing sustainable management practices. Our work shows that this parasite is not consuming hemolymph, as has been the accepted view, but damages host bees by consuming fat body, a tissue roughly analogous to the mammalian liver. Both hemolymph and fat body in honey bees were marked with fluorescent biostains. The fluorescence profile in the guts of mites allowed to feed on these bees was very different from that of the hemolymph of the host bee but consistently matched the fluorescence profile unique to the fat body. Via transmission electron microscopy, we observed externally digested fat body tissue in the wounds of parasitized bees. Mites in their reproductive phase were then fed a diet composed of one or both tissues. Mites fed hemolymph showed fitness metrics no different from the starved control. Mites fed fat body survived longer and produced more eggs than those fed hemolymph, suggesting that fat body is integral to their diet when feeding on brood as well. Collectively, these findings strongly suggest that Varroa are exploiting the fat body as their primary source of sustenance: a tissue integral to proper immune function, pesticide detoxification, overwinter survival, and several other essential processes in healthy bees. These findings underscore a need to revisit our understanding of this parasite and its impacts, both direct and indirect, on honey bee health.