Cocoa ( L.) is an important crop, but yield is generally low. Improving yield requires detailed understanding of the reproductive ecology, especially the pollination system and factors determining pollination success, such as proximity to natural areas. Since the 1940s biting midges have been proposed as the pollinators of cocoa flowers but this idea has recently been questioned in various studies. We observed cocoa flowers and their visitors during anthesis, we compare cocoa flower visitors during the day and night and also in plantations connected and disconnected to natural forests. Observations of flowers during anthesis revealed that cocoa flowers are protandrous, open at night, persist for three days and are receptive only during the day. A diversity of insects visited flowers throughout 24 h. In general, insect visitors were more diverse during the day and in plantations connected to forests compared to those not connected to forests. Fifty five percent of the total insect species visited the cocoa flowers at night, all insect species visited cocoa flowers in plantations connected to natural forests and 62.5 % of those visited cocoa flowers in plantations disconnected with forests. Hymenoptera and Diptera were the main visitors and a total of eleven insect species carried cocoa pollen grains. Among those, two species of biting midges (Ceratopogonidae flies) and two species of stingless bees (Meliponini bees) were the most common. While biting midges were the most common visitors, the stingless bee carried large cocoa pollen loads and interacted with both the male and female parts of the flower. Ants also visited cocoa flowers, mainly at night. The most common visitors of cocoa flowers in cocoa plantations in the upper Magdalena Valley in Colombia are diurnal biting midges and stingless bees, but also nocturnal ants, suggesting that the pollination system of cocoa flowers may be locally less specialized than previously thought. Future research should investigate the effectiveness of various insect groups as pollinators.

中文翻译：

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哥伦比亚马格达莱纳河谷上游可可 (Theobroma cacao L.) 的花卉生物学和花客

可可 (L.) 是一种重要的作物，但产量普遍较低。提高产量需要详细了解生殖生态，特别是授粉系统和决定授粉成功的因素，例如是否接近自然区域。自 20 世纪 40 年代以来，有人提出将蠓作为可可花的传粉者，但这一想法最近在各种研究中受到质疑。我们在开花期间观察了可可花和它们的访客，我们比较了白天和夜间以及与天然林相连和不相连的种植园中的可可花访客。对开花期间花朵的观察表明，可可花是先熟的，在夜间开放，持续三天，并且仅在白天接受花。 24小时内有多种昆虫访问花朵。一般来说，与不与森林相连的种植园相比，白天和与森林相连的种植园中的昆虫访客更加多样化。总昆虫种类的 55% 会在夜间访问可可花，所有昆虫种类都会访问与天然林相连的种植园中的可可花，其中 62.5% 会访问与森林无关的种植园中的可可花。膜翅目和双翅目是主要的来客，共有11种昆虫携带可可花粉粒。其中，两种蠓（Ceratopogonidae 蝇）和两种无刺蜂（Meliponini 蜂）是最常见的。虽然叮蠓是最常见的访客，但无刺蜂携带大量可可花粉，并与花的雄性和雌性部分相互作用。蚂蚁也会拜访可可花，主要是在晚上。在哥伦比亚马格达莱纳河谷上游的可可种植园中，最常见的可可花访客是白天活动的蠓和无刺蜜蜂，但也有夜间活动的蚂蚁，这表明当地可可花的授粉系统可能没有以前想象的那么专业化。未来的研究应该调查各种昆虫群体作为传粉者的有效性。