Deceptive flowers decoy pollinators by advertising a reward, which finally is not provided. Numerous deceptive plants are pollinated by Diptera, but the attractive cues and deceptive strategies are only identified in a few cases. A typical fly-deceptive plant genus is Aristolochia, which evolved sophisticated trap flowers to temporarily capture pollinators. Though rarely demonstrated by experimental approaches, Aristolochia species are believed to chemically mimic brood sites, food sources for adult flies, or utilize sexual deception. Indeed, for most species, studies on scent composition and attractive signals are lacking. In this study, we focused on A. microstoma, a peculiar Greek endemic with flowers that are presented at ground level in the leaf litter or between rocks and are characterized by a unique morphology. We analyzed flower visitor and pollinator spectra and identified the floral scent composition using dynamic headspace and gas chromatography coupled to mass spectrometry (GC/MS). Female and male phorid flies (Phoridae) are the exclusive pollinators, although the flowers are also frequently visited by Sciaridae, as well as typical ground-dwelling arthropods, such as Collembola and arachnids. The carrion-like floral scent mainly consists of the oligosulphides dimethyldi- and dimethyltrisulfide, and the nitrogen-bearing compound 2,5-dimethylpyrazine. These three compounds together are known to be released from decomposing insects, and thus, we conclude that pollinators are likely deceived by chemical imitation of invertebrate carrion, a deceptive strategy not described from another plant species so far.

中文翻译：

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欺骗性马兜​​铃气孔的花朵被磷蝇授粉，并散发出无脊椎动物腐肉中已知的挥发物

欺骗性的花通过广告奖励诱骗传粉媒介，但最终没有提供。双歧杆菌对许多欺骗性植物进行授粉，但只有少数情况才能确定诱人的线索和欺骗策略。典型的会诱蝇的植物属马兜铃属（Aristolochia），其进化出复杂的陷阱花以暂时捕获授粉媒介。尽管很少通过实验方法证明，但马兜铃物种被认为在化学上模仿了繁殖场所，成年苍蝇的食物来源或利用了性欺骗。确实，对于大多数物种而言，缺乏对气味成分和诱人信号的研究。在这项研究中，我们集中于微小气孔菌（A. microstoma），这是希腊特有的种花，在地面上的叶凋落物或岩石之间呈花朵状，并具有独特的形态特征。我们分析了访客花和传粉者的光谱，并使用动态顶空和气相色谱-质谱联用技术（GC / MS）鉴定了花香成分。雌性和雄性类蝇（Phoridae）是唯一的传粉媒介，尽管这些花也经常被S虫科以及典型的陆生节肢动物（如Collembola和蜘蛛纲动物）所探访。腐肉状的花香主要由低聚硫化物二甲基二硫和二甲基三硫以及含氮化合物2,5-二甲基吡嗪组成。已知这三种化合物一起从分解的昆虫中释放出来，因此，我们得出的结论是，授粉媒介很可能是通过化学模仿无脊椎动物腐肉而被欺骗的，到目前为止，还没有从其他植物物种中描述过这种欺骗性策略。