Sexually deceptive orchids mimic signals emitted by female insects in order to attract mate-searching males. Specific attraction of the targeted pollinator is achieved by sex pheromone mimicry, which constitutes the major attraction channel. In close vicinity of the flower, visual signals may enhance attraction, as was shown recently in the sexually deceptive orchid Ophrys heldreichii. Here, we conducted an in situ manipulation experiment in two populations of O. heldreichii on Crete to investigate whether the presence/absence of the conspicuous pink perianth affects reproductive success in two natural orchid populations. We estimated reproductive success of three treatment groups (with intact, removed and artificial perianth) throughout the flowering period as pollinaria removal (male reproductive success) and massulae deposition (female reproductive success). Reproductive success was significantly increased by the presence of a strong visual signal—the conspicuous perianth—in one study population, however, not in the second, most likely due to the low pollinator abundance in the latter population. This study provides further evidence that the coloured perianth in O. heldreichii is adaptive and thus adds to the olfactory signal to maximise pollinator attraction and reproductive success.

中文翻译：

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花卉视觉信号增加了性欺骗兰花的繁殖成功率。

性欺骗兰花模仿雌性昆虫发出的信号，以吸引寻找配偶的雄性。对目标授粉者的特定吸引是通过性信息素模仿来实现的，它构成了主要的吸引渠道。在花的附近，视觉信号可能会增强吸引力，正如最近在性欺骗性兰花Ophrysheldreichii 中所显示的那样。在这里，我们在两个O.heldreichii种群中进行了原位操作实验在克里特岛调查显眼的粉红色花被的存在/不存在是否会影响两个天然兰花种群的繁殖成功。我们估计了整个开花期三个处理组（完整、去除和人工花被）的繁殖成功率，如去除花粉（雄性繁殖成功）和马苏勒沉积（雌性繁殖成功）。在一个研究群体中，由于存在强烈的视觉信号（显眼的花被），繁殖成功率显着提高，但在第二个群体中却没有，这很可能是由于后一个群体的传粉媒介丰度低。本研究进一步证明O.heldreichii的有色花被 是适应性的，因此增加了嗅觉信号，以最大限度地提高传粉者的吸引力和繁殖成功率。