Favaro Riccardo, Roved Jacob, Haase Albrecht, Angeli Sergio
Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.
Section for Evolutionary Genomics, Faculty of Health and Medical Sciences, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark.
Front Insect Sci. 2022 Apr 18;2:821145. doi: 10.3389/finsc.2022.821145. eCollection 2022.
Volatile compounds provide important olfactory cues for honey bees ( L.), which are essential for their ecology, behavior, and social communication. In the external environment bees locate food sources by the use of floral scents, while inside the hive, pheromones such as the queen mandibular pheromone (QMP) and alarm pheromones serve important functions in regulating colony life and inducing aggressive responses against intruders and parasites. Widely reported alterations of various behaviors in- and outside the hive following exposure to pesticides could therefore be associated with a disturbance of odor sensitivity. In the present study, we tested the effects of neonicotinoid pesticides at field concentrations on the ability of honey bees to perceive volatiles at the very periphery of the olfactory system. Bee colonies were subjected to treatments during the summer with either Imidacloprid or Thiacloprid at sublethal concentrations. Antennal responses to apple ( L.) flower volatiles were studied by GC-coupled electro-antennographic detection (GC-EAD), and a range of volatiles, a substitute of the QMP, and the alarm pheromone 2-heptanone were tested by electroantennography (EAG). Short-term and long-term effects of the neonicotinoid treatments were investigated on bees collected in the autumn and again in the following spring. Treatment with Thiacloprid induced changes in antennal responses to specific flower VOCs, with differing short- and long-term effects. In the short term, increased antennal responses were observed for benzyl-alcohol and 1-hexanol, which are common flower volatiles but also constituents of the honey bee sting gland secretions. The treatment with Thiacloprid also affected antennal responses to the QMP and the mandibular alarm pheromone 2-heptanone. In the short term, a faster signal degeneration of the response signal to the positive control citral was recorded in the antennae of bees exposed to Thiacloprid or Imidacloprid. Finally, we observed season-related differences in the antennal responses to multiple VOCs. Altogether, our results suggest that volatile-specific alterations of antennal responses may contribute to explaining several behavioral changes previously observed in neonicotinoid-exposed bees. Treatment effects were generally more prominent in the short term, suggesting that adverse effects of neonicotinoid exposure may not persist across generations.
挥发性化合物为蜜蜂提供了重要的嗅觉线索，这对它们的生态、行为和社会交流至关重要。在外部环境中，蜜蜂通过花香来定位食物来源，而在蜂巢内部，诸如蜂王颚腺信息素（QMP）和警报信息素等信息素在调节蜂群生活以及引发对入侵者和寄生虫的攻击反应中发挥着重要作用。因此，广泛报道的接触农药后蜂巢内外各种行为的改变可能与气味敏感性的干扰有关。在本研究中，我们测试了田间浓度的新烟碱类农药对蜜蜂在嗅觉系统最外周感知挥发性物质能力的影响。在夏季，蜂群接受了亚致死浓度的吡虫啉或噻虫啉处理。通过气相色谱联用触角电位检测（GC-EAD）研究触角对苹果花挥发性物质的反应，并通过触角电位图（EAG）测试了一系列挥发性物质、QMP的替代品以及警报信息素2-庚酮。研究了新烟碱类处理对秋季采集的蜜蜂以及次年春季再次采集的蜜蜂的短期和长期影响。噻虫啉处理导致触角对特定花朵挥发性有机化合物（VOCs）的反应发生变化，短期和长期影响不同。短期内，观察到苯甲醇和1-己醇的触角反应增强，这两种物质既是常见的花朵挥发性物质，也是蜜蜂螫腺分泌物的成分。噻虫啉处理还影响了触角对QMP和颚部警报信息素2-庚酮的反应。短期内，在接触噻虫啉或吡虫啉的蜜蜂触角中，记录到对阳性对照柠檬醛的反应信号退化更快。最后，我们观察到触角对多种VOCs的反应存在季节相关差异。总之，我们的结果表明，触角反应的挥发性物质特异性改变可能有助于解释先前在接触新烟碱类的蜜蜂中观察到的几种行为变化。处理效果通常在短期内更为显著，这表明新烟碱类暴露的不利影响可能不会跨代持续存在。
