Brandt Katharina, Dötterl Stefan, Francke Wittko, Ayasse Manfred, Milet-Pinheiro Paulo
Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany.
Department of Ecology & Evolution, University of Salzburg, Salzburg, Austria.
J Chem Ecol. 2017 Jan;43(1):4-12. doi: 10.1007/s10886-016-0802-z. Epub 2016 Dec 28.
The pollen diet provided by adult bees to their offspring varies immensely. While some species collect pollen on several plants irrespective of their phylogenetic relatedness (polyleges), others collect only on plants within a genus or family (oligoleges). Floral scents play a central role in bee-plant interactions. To locate flowers, polyleges are assumed to rely on compounds commonly found as floral scent constituents, whereas oligoleges rely on unusual compounds to recognize host flowers unambiguously. Campanula flowers are visited by both polylectic and oligolectic species, and their scent bouquets consist of common and unusual (e.g., spiroacetals) volatiles. In a comparative approach, we performed electroantennographic analyses to investigate the antennal responses of three polyleges and three oligoleges to three common volatiles and four spiroacetals. We hypothesized that: 1) oligoleges and polyleges should respond similarly to common flower volatiles, and 2) Campanula oligoleges should be more sensitive to spiroacetals than are polyleges. In corroboration, we found that antennal sensitivity to common volatiles was similar among bees irrespective of pollen diet, whereas oligoleges of Campanula were more sensitive to spiroacetals than polyleges. Newly emerged bees of the Campanula oligolege Chelostoma rapunculi rely on spiroacetals for recognizing host-flowers, and our results suggest that this might also be true for other Campanula oligoleges, since Chelostoma campanularum and Hoplitis mitis also were able to perceive these specific volatiles at very low concentrations. Together, our results provide interesting insights into the significance of olfactory adaptations in oligolectic and polylectic bee species.
成年蜜蜂为其后代提供的花粉食物差异极大。有些物种会在多种植物上采集花粉，而不考虑这些植物的系统发育关系（多聚采集者），另一些则只在一个属或科的植物上采集花粉（寡聚采集者）。花香在蜜蜂与植物的相互作用中起着核心作用。为了找到花朵，多聚采集者被认为依赖于常见的花香成分化合物，而寡聚采集者则依赖于不寻常的化合物来明确识别寄主花朵。风铃草花会被多聚采集者和寡聚采集者光顾，其花香由常见和不寻常的（如螺缩醛）挥发物组成。我们采用比较研究方法，进行了触角电图分析，以研究三种多聚采集者和三种寡聚采集者对三种常见挥发物和四种螺缩醛的触角反应。我们假设：1）寡聚采集者和多聚采集者对常见花香挥发物的反应应相似；2）风铃草寡聚采集者对螺缩醛的敏感度应高于多聚采集者。经证实，我们发现，无论花粉食物如何，蜜蜂对常见挥发物的触角敏感度相似，而风铃草寡聚采集者对螺缩醛的敏感度高于多聚采集者。风铃草寡聚采集者拉氏切叶蜂新羽化的蜜蜂依靠螺缩醛来识别寄主花朵，我们的研究结果表明，其他风铃草寡聚采集者可能也是如此，因为钟形切叶蜂和细纹准蜂也能够在极低浓度下感知这些特定的挥发物。总之，我们的研究结果为寡聚采集和多聚采集蜜蜂物种嗅觉适应的重要性提供了有趣的见解。
