Departamento de Apicultura Tropical, Campus Ciencias Biológicas y Agropecuarias, Mérida-Xmatkuil, Mexico.
Department of Forestry, Michigan State University, East Lansing, MI, United States of America.
PLoS One. 2024 Jul 24;19(7):e0306808. doi: 10.1371/journal.pone.0306808. eCollection 2024.
Vanilla planifolia is native to the Mexican tropics. Despite its worldwide economic importance as a source of vanilla for flavoring and other uses, almost all vanilla is produced by expensive hand-pollination, and minimal documentation exists for its natural pollination and floral visitors. There is a claim that vanilla is pollinated by Melipona stingless bees, but vanilla is more likely pollinated by orchid bees. Natural pollination has not been tested in the Yucatán region of Mexico, where both vanilla and potential native bee pollinators are endemic. We document for the first time the flowering process, nectar production and natural pollination of V. planiflora, using bagged flower experiments in a commercial planting. We also assessed the frequency and visitation rates of stingless bees and orchid bees on flowers. Our results showed low natural pollination rates of V. planifolia (~ 5%). Only small stingless bees (Trigona fulviventris and Nannotrigona perilampoides) were seen on flowers, but no legitimate visits were witnessed. We verified that there were abundant Euglossa and fewer Eulaema male orchid bees around the vanilla plants, but neither visited the flowers. The introduction of a colony of the stingless bee Melipona beecheii and the application of chemical lures to attract orchid bees failed to induce floral visitations. Melipona beecheii, and male orchid bees of Euglossa viridissima and E. dilemma may not be natural pollinators of vanilla, due to lack of attraction to flowers. It seems that the lack of nectar in V. planifolia flowers reduces the spectrum of potential pollinators. In addition, there may be a mismatch between the attractiveness of vanilla floral fragrances to the species of orchid bees registered in the studied area. Chemical studies with controlled experiments in different regions would be important to further elucidate the potential pollinators of vanilla in southern Mexico.
香荚兰原产于墨西哥热带地区。尽管香荚兰作为调味剂和其他用途的香草来源在世界范围内具有重要的经济价值，但几乎所有的香草都是通过昂贵的人工授粉生产的，而且对其自然授粉和花卉传粉者的记录很少。有人声称香草是由无刺蜜蜂授粉的，但香草更有可能是由兰花蜜蜂授粉的。在墨西哥尤卡坦地区，尚未对香草及其潜在的本地传粉蜜蜂进行自然授粉测试，因为那里既有香草又有本地的传粉蜜蜂。我们首次记录了香荚兰的开花过程、花蜜产生和自然授粉过程，在商业种植中使用套袋花朵实验进行了记录。我们还评估了无刺蜜蜂和兰花蜜蜂在花朵上的出现频率和访问率。我们的结果表明，香荚兰的自然授粉率较低（约 5%）。只有小型无刺蜜蜂（Trigona fulviventris 和 Nannotrigona perilampoides）在花朵上被观察到，但没有看到合法的访问。我们证实，在香草植物周围有大量的 Euglossa 和较少的 Eulaema 雄性兰花蜜蜂，但它们都没有访问花朵。引入无刺蜜蜂 Melipona beecheii 的殖民地和应用化学诱饵来吸引兰花蜜蜂都未能诱使花朵访问。由于缺乏对花朵的吸引力，无刺蜜蜂 Melipona beecheii 和 Euglossa viridissima 和 E. dilemma 的雄性兰花蜜蜂可能不是香草的天然传粉者。似乎香荚兰花朵花蜜的缺乏减少了潜在传粉者的范围。此外，在所研究地区登记的兰花蜜蜂种类对香草花香的吸引力可能存在不匹配。在不同地区进行的控制实验的化学研究对于进一步阐明墨西哥南部香草的潜在传粉者将非常重要。
