Chen Gao, Jürgens Andreas, Shao Lidong, Liu Yang, Sun Weibang, Xia Chengfeng
Kunming Botanical Garden, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650204, Yunnan, China.
J Chem Ecol. 2015 Mar;41(3):244-52. doi: 10.1007/s10886-015-0563-0. Epub 2015 Apr 3.
By emitting scent resembling that of organic material suitable for oviposition and/or consumption by flies, sapromyophilous flowers use these flies as pollinators. To date, intensive scent analyses of such flowers have been restricted to Apocynaceae, Annonaceae, and Araceae. Recent studies have suggested that the wide range of volatile organic compounds (VOCs) from sapromyophilous flowers play an important role in attracting saprophagous flies by mimicking different types of decomposing substrates (herbivore and carnivore feces, carrion, and the fruiting bodies of fungi, etc.). In this study, we report the flower visitors and the floral VOCs of Stemona japonica (Blume) Miquel, a species native to China. The flowers do not produce rewards, and pollinators were not observed consuming pollen, thus suggesting a deceptive pollination system. Headspace samples of the floral scent were collected via solid-phase micro-extraction and analysed by gas chromatography coupled with mass spectrometry. Main floral scent compounds were 1-pyrroline (59.2%), 2-methyl-1-butanol (27.2%), and 3-methyl-1-butanol (8.8%), and resulted in a semen-like odor of blooming flowers. The floral constituents of S. japonica were significantly different from those found in previous sapromyophilous plants. An olfaction test indicated that 1-pyrroline is responsible for the semen-like odor in S. japonica flowers. Main flower visitors were shoot flies of the genus Atherigona (Muscidae). Bioassays using a mixture of all identified floral volatiles revealed that the synthetic volatiles can attract Atherigona flies in natural habitats. Our results suggest that the foul-smelling flowers of S. japonica may represent a new type of sapromyophily through scent mimicry.
通过散发类似适合苍蝇产卵和/或食用的有机物质的气味，嗜尸花利用这些苍蝇作为传粉者。迄今为止，对这类花朵的深入气味分析仅限于夹竹桃科、番荔枝科和天南星科。最近的研究表明，嗜尸花中广泛的挥发性有机化合物（VOCs）通过模仿不同类型的分解底物（食草动物和食肉动物的粪便、腐肉以及真菌的子实体等），在吸引食腐苍蝇方面发挥着重要作用。在本研究中，我们报告了中国本土物种日本百部（Stemona japonica (Blume) Miquel）的访花者和花香挥发性有机化合物。这些花朵不产生报酬，且未观察到传粉者消耗花粉，因此表明这是一种欺骗性传粉系统。通过固相微萃取收集花香的顶空样品，并采用气相色谱-质谱联用进行分析。主要的花香化合物为1-吡咯啉（59.2%）、2-甲基-1-丁醇（27.2%）和3-甲基-1-丁醇（8.8%），这些成分使盛开的花朵产生类似精液的气味。日本百部的花成分与之前发现的嗜尸植物显著不同。嗅觉测试表明，1-吡咯啉是日本百部花中类似精液气味的来源。主要的访花者是阿瘿蚊属（Atherigona）（蝇科）的茎蝇。使用所有已鉴定的花香挥发物混合物进行的生物测定表明，合成挥发物能够在自然栖息地吸引阿瘿蚊属苍蝇。我们的结果表明，日本百部气味难闻的花朵可能通过气味模仿代表了一种新型的嗜尸现象。
