Institute for Bee Research, Friedrich-Engels-Strasse 32, 16540 Hohen Neuendorf, Germany.
J Exp Biol. 2012 Jan 15;215(Pt 2):264-71. doi: 10.1242/jeb.062562.
The ectoparasitic mite Varroa destructor and honey bee pathogenic viruses have been implicated in the recent demise of honey bee colonies. Several studies have shown that the combination of V. destructor and deformed wing virus (DWV) poses an especially serious threat to honey bee health. Mites transmitting virulent forms of DWV may cause fatal DWV infections in the developing bee, while pupae parasitised by mites not inducing or activating overt DWV infections may develop normally. Adult bees respond to brood diseases by removing affected brood. This hygienic behaviour is an essential part of the bees' immune response repertoire and is also shown towards mite-parasitised brood. However, it is still unclear whether the bees react towards the mite in the brood cell or rather towards the damage done to the brood. We hypothesised that the extent of mite-associated damage rather than the mere presence of parasitising mites triggers hygienic behaviour. Hygienic behaviour assays performed with mites differing in their potential to transmit overt DWV infections revealed that brood parasitised by 'virulent' mites (i.e. mites with a high potential to induce fatal DWV infections in parasitised pupae) were removed significantly more often than brood parasitised by 'less virulent' mites (i.e. mites with a very low potential to induce overt DWV infections) or non-parasitised brood. Chemical analyses of brood odour profiles suggested that the bees recognise severely affected brood by olfactory cues. Our results suggest that bees show selective, damage-dependent hygienic behaviour, which may be an economic way for colonies to cope with mite infestation.
外寄生螨虫瓦螨和蜜蜂病原病毒与最近蜜蜂种群的灭绝有关。多项研究表明，瓦螨和变形翅膀病毒（DWV）的组合对蜜蜂健康构成了特别严重的威胁。传播致命形式 DWV 的螨虫可能会导致发育中的蜜蜂致命的 DWV 感染，而被未诱导或激活明显 DWV 感染的螨虫寄生的蛹可能会正常发育。成年蜜蜂通过清除受感染的幼虫来应对幼虫疾病。这种卫生行为是蜜蜂免疫反应库的重要组成部分，也针对螨虫寄生的幼虫表现出来。然而，目前尚不清楚蜜蜂是对幼虫细胞中的螨虫做出反应，还是对螨虫对幼虫造成的损害做出反应。我们假设，与螨虫相关的损害程度而不是寄生螨虫的存在会引发卫生行为。用在传播明显 DWV 感染能力上存在差异的螨虫进行的卫生行为分析表明，被“毒力”螨虫寄生的幼虫（即具有在寄生蛹中诱导致命 DWV 感染的高潜力的螨虫）比被“毒力较弱”的螨虫寄生的幼虫（即具有在寄生蛹中诱导明显 DWV 感染的极低潜力的螨虫）或未被寄生的幼虫被清除的频率明显更高。对幼虫气味特征的化学分析表明，蜜蜂通过嗅觉线索识别受严重影响的幼虫。我们的结果表明，蜜蜂表现出有选择性的、依赖于损害的卫生行为，这可能是蜂群应对螨虫侵袭的一种经济方式。
