Department of Biochemistry & Molecular Biology and Michael Smith Laboratories, University of British Columbia, 2125 East Mall, Vancouver, British Columbia, Canada.
Dipartimento di Biologia Università degli Studi di Firenze Via Madonna del Piano 6, 50019, Sesto Fiorentino, Italy.
Sci Rep. 2018 Apr 9;8(1):5719. doi: 10.1038/s41598-018-24054-2.
Eusocial insects live in teeming societies with thousands of their kin. In this crowded environment, workers combat disease by removing or burying their dead or diseased nestmates. For honey bees, we found that hygienic brood-removal behavior is triggered by two odorants - β-ocimene and oleic acid - which are released from brood upon freeze-killing. β-ocimene is a co-opted pheromone that normally signals larval food-begging, whereas oleic acid is a conserved necromone across arthropod taxa. Interestingly, the odorant blend can induce hygienic behavior more consistently than either odorant alone. We suggest that the volatile β-ocimene flags hygienic workers' attention, while oleic acid is the death cue, triggering removal. Bees with high hygienicity detect and remove brood with these odorants faster than bees with low hygienicity, and both molecules are strong ligands for hygienic behavior-associated odorant binding proteins (OBP16 and OBP18). Odorants that induce low levels of hygienic behavior, however, are weak ligands for these OBPs. We are therefore beginning to paint a picture of the molecular mechanism behind this complex behavior, using odorants associated with freeze-killed brood as a model.
群居昆虫生活在有成千上万同类的繁荣社会中。在这种拥挤的环境中，工蜂通过清除或掩埋死去或患病的同巢伙伴来抵抗疾病。对于蜜蜂，我们发现卫生的幼体清除行为是由两种气味物质 - β-罗勒烯和油酸 - 触发的，这两种物质是从被冷冻杀死的幼体中释放出来的。β-罗勒烯是一种被共选作信息素的物质，通常用于信号幼虫食物乞讨，而油酸是节肢动物门中保守的尸体气味物质。有趣的是，气味混合物比单独的任何一种气味物质都更能一致地诱导卫生行为。我们认为挥发性的β-罗勒烯标志着卫生工人的注意力，而油酸是死亡信号，触发清除。具有高卫生性的蜜蜂比低卫生性的蜜蜂更快地检测和清除带有这些气味物质的幼体，并且这两种分子都是卫生行为相关的气味结合蛋白（OBP16 和 OBP18）的强配体。然而，诱导低水平卫生行为的气味物质是这些 OBPs 的弱配体。因此，我们开始使用与冷冻杀死的幼体相关的气味物质作为模型，描绘这种复杂行为背后的分子机制。
