Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany.
Natural History Museum, National University of San Marcos, Lima, Peru.
Plant Biol (Stuttg). 2019 Jul;21(4):723-731. doi: 10.1111/plb.12974. Epub 2019 Mar 1.
Although common among orchids, pollination by perfume-gathering male euglossine bees is quite rare in other Neotropical families. In Gesneriaceae, for example, it is reported in two genera only, Drymonia and Gloxinia. Flowers of G. perennis are known to emit perfume, thereby attracting male euglossine bees as pollinators. However, detailed reports on the pollination ecology, as well as on chemistry of floral perfume of individuals in natural populations, are still missing. In this study, we report on the pollination ecology of G. perennis, focusing on the ecological significance of its floral perfume. In natural populations in Peru, we documented the floral biology and breeding system of G. perennis, as well as its interaction with flower visitors. We also characterised the chemical composition of floral perfume, as well as its timing of emission. Gloxinia perennis is self-compatible and natural pollination success is high. Spontaneous self-pollination occurs as a 'just in case strategy' when pollinators are scarce. Perfume-collecting males of Eulaema cingulata and El. meriana were identified as pollinators. The perfume bouquet of G. perennis consists of 16 compounds. (E)-Carvone epoxide (41%) and limonene (23%) are the major constituents. Perfume emission is higher at 09:00 h, matching the activity peak of Eulaema pollinators. Flowers of G. perennis have evolved a mixed strategy to ensure pollination (i.e. self- and cross-pollination), but cross-pollination is favoured. The size and behaviour of Eulaema males enables only these bees to successfully cross-pollinate G. perennis. Furthermore, G. perennis floral perfume traits (i.e. chemistry and timing of emission) have evolved to optimise the attraction of these bees.
虽然在兰花中很常见，但香水收集雄 Euglossine 蜜蜂授粉在其他新热带科中相当罕见。例如，在苦苣苔科中，仅在两个属中报道，即 Drymonia 和 Gloxinia。已知 G. perennis 的花朵会散发香水，从而吸引雄性 Euglossine 蜜蜂作为传粉者。然而，关于其授粉生态学以及自然种群中个体花香化学的详细报告仍然缺失。在这项研究中，我们报告了 G. perennis 的授粉生态学，重点关注其花香的生态意义。在秘鲁的自然种群中，我们记录了 G. perennis 的花生物学和繁殖系统，以及它与花访客的相互作用。我们还描述了花香的化学组成及其排放的时间。Gloxinia perennis 是自交亲和的，自然授粉成功率很高。当传粉者稀少时，自发的自花授粉会作为“以防万一的策略”发生。Eulaema cingulata 和 El. meriana 的香水收集雄蜂被鉴定为传粉者。G. perennis 的香水组合由 16 种化合物组成。(E)-香芹酮环氧化物（41%）和柠檬烯（23%）是主要成分。香水排放的高峰期在 09:00 时，与 Euglossine 传粉者的活动高峰期相匹配。G. perennis 的花朵已经进化出一种混合策略来确保授粉（即自交和异交），但异交更有利。Eulaema 雄蜂的大小和行为使这些蜜蜂能够成功地异交 G. perennis。此外，G. perennis 花香特征（即化学组成和排放时间）已经进化到能够优化这些蜜蜂的吸引力。
