Institute for Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, D-89069 Ulm, Germany.
Phytochemistry. 2011 Sep;72(13):1667-77. doi: 10.1016/j.phytochem.2011.03.023. Epub 2011 Apr 15.
Sexually deceptive orchids mimic females of their pollinator species to attract male insects for pollination. Pollination by sexual deception has independently evolved in European, Australian, South African, and South American orchid taxa. Reproductive isolation is mainly based on pre-mating isolation barriers, the specific attraction of males of a single pollinator species, mostly bees, by mimicking the female species-specific sex-pheromone. However, in rare cases post-mating barriers have been found. Sexually deceptive orchids are ideal candidates for studies of sympatric speciation, because key adaptive traits such as the pollinator-attracting scent are associated with their reproductive success and with pre-mating isolation. During the last two decades several investigations studied processes of ecological speciation in sexually deceptive orchids of Europe and Australia. Using various methods like behavioural experiments, chemical, electrophysiological, and population-genetic analyses it was shown that minor changes in floral odour bouquets might be the driving force for pollinator shifts and speciation events. New pollinators act as an isolation barrier towards other sympatrically occurring species. Hybridization occurs because of similar odour bouquets of species and the overlap of flowering periods. Hybrid speciation can also lead to the displacement of species by the hybrid population, if its reproductive success is higher than that in the parental species.
有性欺骗的兰花通过模拟其传粉者物种的雌性来吸引雄性昆虫进行传粉。这种有性欺骗在欧洲、澳大利亚、南非和南美洲的兰花分类群中独立进化而来。生殖隔离主要基于交配前的隔离障碍，即通过模拟雌性物种特有的性信息素来吸引单一传粉者物种（大多是蜜蜂）的雄性。然而，在极少数情况下也发现了交配后的障碍。有性欺骗的兰花是研究同域物种形成的理想候选者，因为吸引传粉者的气味等关键适应性特征与它们的繁殖成功和交配前的隔离有关。在过去的二十年中，一些研究调查了欧洲和澳大利亚的有性欺骗兰花的生态物种形成过程。通过行为实验、化学、电生理学和群体遗传学分析等各种方法，研究表明，花卉气味组合的微小变化可能是推动传粉者转变和物种形成事件的驱动力。新的传粉者成为其他同域发生的物种的隔离障碍。由于物种的气味组合相似以及开花期重叠，杂交会发生。如果杂种的繁殖成功率高于亲种，杂种形成也会导致杂种种群取代物种。
