On a recent trip to northern Thailand (Chiang Dao) I came across these strange tubes coming out of the bottom of a tree. I knew at once that they were the nest entrance tubes of stingless bees (Meliponini) but I had no idea what species made them.
There are at least 45 described species of stingless bees (Apinae: Corbiculata: Meliponini) in Southeast Asia and many more remain undescribed (Cortopassi-Laurino et al., 2006). However, the shapes of the nest entrances are characteristic of a given species, so it did not take much searching to discover that these tubes were probably made by Trigona collina (also known as Tetragonula collina). There were a number of nest entrance tubes emerging from the base of this tree – so perhaps leading down to one large colony? – and the little bees were constantly coming and going (see below). It is thought that the tall, slippery, waxy tubes stop ants and other predators from gaining access to the nests, and the bees regularly add fresh wax to the top of the tube to maintain this property.
For photos of stingless bees by Fauziah Shariff on Flickr, see here. For a key to Indo-Malayan Stingless Bees, which probably includes many found in Thailand – see here. The size and appearance of stingless bees varies greatly, as shown below.
Stingless bees live in colonies, and like honey bees, produce wax and honey. Workers forage for pollen and nectar to feed the larvae. To construct their nests and nest entrances, the workers also collect resin from trees, such as this large dipterocarp resin tree, Dipterocarpus alatus, shown below. A number of other insects, including spiders, ants, moths and resin bugs are also drawn to these resin traps.
Inside the nest of stingless bees, there are brood cells and food storage containers of different sizes and shapes; the honey is stored in little pots of various sizes depending on the species (Rattanawannee & Chanchao, 2011). The brood cells are filled with honey and pollen by the worker bees prior to the queen laying an egg in them. The cells then remain sealed as the bee develops and an adult bee eventually emerges. A video of a stingless bee colony (hive) is shown here. Stingless bee honey can command quite a premium. Thai stingless bee honey reportedly retails for 1,200 -1,500 THB (c. $40-$50 USD) per kg! Much more expensive than honey produced by Apis mellifera.
In eusocial insects such as these there are different castes: reproductive females (queens); reproductive males (drones) and sterile, non-reproductive females (workers). The caste system is somewhat variable in stingless bees and is determined by the amount of pollen an individual consumes! Larger amounts of pollen yield queens.
I have written about a different species of stingless bee before, one that makes another sort of nest entrance (shown below) and is therefore a different species. It was located at the base of the same sort of large dipterocarp tree. I called this Trigona sp. before, but I think it may be Trigona (Tetrigona) apicalis, based on the shape of the nest entrance. It is a relatively large bee with white-tipped wings.
Stingless bees may lack the ability to deliver a sting, but they are not defenseless: they can bite! And the most aggressive ones are often the smallest; such as Tetragonula fuscobalteata, which nest in bamboo stem cavities.
According to Rattanawannee and Chanchao (2011), the Thai names for stingless bees are as follows: Channa Rong (Central), Kheetung Nee (North), Khee Suit (Northeast), and Oong (South).
Stingless bees are hugely important members of tropical or subtropical ecosystems and although sometimes overshadowed by their apine (apid?) cousins, they are known to help pollinate at least 60 crop species (Heard, 1999).
Chuttong, B., Chanbang, Y. & Burgett, M. (2014). Meliponiculture: Stingless Bee Beekeeping in Thailand. Bee World, 91(2), 41-45.
Cortopassi-Laurino, M., Imperatriz-Fonseca, V. L., Roubik, D. W., Dollin, A., Heard, T., Aguilar, I., … & Nogueira-Neto, P. (2006). Global meliponiculture: challenges and opportunities. Apidologie, 37(2), 275-292.
Heard, T. A. (1999). The role of stingless bees in crop pollination. Annual review of entomology, 44(1), 183-206.
Rattanawannee, A. & Chanchao, C. (2011). Bee diversity in Thailand and the applications of bee products. Changing Diversity in Changing Environment. InTech, Rijeka, 133-62.