The Eastern honey bee, or Asian honey bee (Apis cerana), is endemic to much of Asia where has been cultivated for honey production for millenia. It is fairly similar to the European, or Western honey bee (Apis mellifera), but is slightly smaller and its flight is faster and more erratic. They are less domesticated and produce less honey than Apis mellifera but they have the advantage of being resistant to Varroa mites and predatory wasps. The vast majority of A. cerana bees still live in the wild, and domesticated colonies tend to swarm, abscond and migrate quite frequently. In other words, they go AWOL! Nevertheless, they provide honey, beeswax, and of course, the vital and invaluable service of crop pollination. They are known to visit and pollinate more than 68 plant species, including many important crops such as: cashew nut trees, coconut palms, coffee bushes and so on.
They are highly adaptable and occur in a wide range of habitats, from rain-forests to savannas. I came across these bees collecting pollen and nectar on Calla (or Arum) lily flowers (Zantedeschia aethiopica) in northern Thailand; in the mountain resort and Royal Agricultural Station of Doi Ang Khang.
The biology of these flowers is interesting. As the flower develops and opens, it goes through a number of stages: prefemale, female and then male. The actual flowers of Zantedeschia are arranged on a fleshy yellow spike (called a spadix) which is enclosed in a large, white, leaf-like bract, called the spathe. The upper portion of the spadix is covered in a dense mass of stamens fixed to male flowers (see below); whilst the female flowers are located further down the spadix in a zone at the base.
The female phase occurs first, as the spathe begins to unwind. For about six days, the flowers are receptive to pollination. The flowers are ‘self-incompatible‘ so they need the pollen of another flower to pollinate them; insects such a beetles, and presumably these bees, play an important role in this process.
As the spathe opens more fully, as in these photographs, the male phase begins: all the anthers on the spadix dehisce – burst open – at the same time and flowering lasts for about 10 days. The pollen grains are extruded through pores in the anthers, in fine long threads held together by a sticky substance; these attach themselves to the bodies of insects. The way that the bees are feeding (below) suggests that there is nectar within the spadix, and not just associated with the female flowers?
The pollen sacs on these bees visiting Calla lilies is very white. On other flowers, the pollen may be a different colour, such as orange or yellow, as shown in the following two photos of Asiatic honey bees (Apis cerana) on purple coneflower and on an unidentified yellow flower, respectively.
Singh, Y., Van Wyk, A. E., & Baijnath, H. (1996). Floral biology of Zantedeschia aethiopica (L.) Spreng.(Araceae). South African Journal of Botany, 62(3), 146-150.
Suwannapong, G., Benbow, M. E., & Nieh, J. C. (2011). Biology of Thai honeybees: natural history and threats. In: In: Bees: Biology, Threats and Colonies, Editor: Richard M. Florio, pp. 1-98. ISBN # 978-1-61324-825-6