Stingless Bees (Tetragonula carbonaria) or Sugarbag bees are much smaller and less noticeable than honey bees. Once they came to my attention though, I found them intriguing. I first spotted them in our front garden around a Crepe Myrtle. Their plain black upright silhouettes against a dark background made me think of sci-fi movie space pods:
Then I got closer to one on a Tecoma flower. I could see its stubbly white hair growth and the three simple eyes on the top of its head complementing its two larger compound eyes :
Like honey bees, Sugarbag bees carry their pollen load in a pair of pollen baskets or corbiculae on their third pair of legs. The corbiculae are held low, so they could also act as stabilisers in flight. Each corbicula consists of a hollowed area on the leg surrounded by hairs which trap the pollen (made stickier with honey or nectar). The colour varies with the type of pollen collected; this bee’s baskets are full of bright yellow crepe myrtle pollen:
Compare the last bee with this one on a ficifolia blossom, whose corbiculae are laden with much paler creamy-brown pollen. You can also just distinguish some of the individual ommatidia that make up her compound eye, as well as some of the hairs on her body:
Despite their small size (about 6mm), stingless bees seem to hold their own in competition with other bees. I took this series of photos on a mass of bloodwood flowers (Corymbia ficifolia) one Christmas Day. The series starts with a masked bee and a stingless bee gathering pollen.
Then a honey bee comes barrelling in and shoves the two smaller bees aside:
But not for long. When it moves to the next bloom, the honey bee gets its come-uppance as a stingless bee spots its unguarded rear end:
The stingless bee swoops in:
And claims its prize:
Gathering pollen can be a dusty business, as this picture taken on a crepe myrtle shows:
At this scale you realise that a simple business like using 6 legs to clamber around a crepe myrtle flower requires quite sophisticated body control, balance and reflexes. Here a bee is stretching her full length from a petal to reach the next stamen.
Which gives a good view of her full corbicula:
All of the bees foraging in these photos are older bees. The younger bees tend the nest and the brood cells, and only go foraging as they age.
Like honey bees, stingless bees have a queen bee and drones to take care of reproduction, and female worker bees to take care of everything else. However unlike honey bees, drones and rival queens are not usually killed off. A number of drones are allowed to survive, and while only one queen at a time mates and lays eggs, there is usually a small reserve of virgin queens held in case the queen dies or loses fertility. As a further backup, the larvae of worker bees can also be allowed to develop as queens.
The chosen queen then takes a mating flight into a congregation of males gathered from nearby nests – attracted presumably by pheromones from the queen. One lucky male mates with the queen (and dies immediately!), after which she returns to her nest with a lifetime store of sperm. She never mates again.
The next photo shows the outside of a naturally built nest in a hollow tree stump. Item 1 is the entrance to the nest cavity, 2 is waste being taken out by a worker, 3 is a dead bee being removed, items 4 and 5 are returning foragers identifiable by the yellow pollen in their corbiculae, and 6 shows the expanse of propolis outside the nest. Propolis is a mixture of beeswax and plant resins; most of the resins have antimicrobial properties that the bees use to protect the hive entrance:
The bees will also happily accept a suitable artificial nest box, like this one in a neighbour’s back yard.
Unfortunately I don’t yet have a photo of the interior of a nest. Midwinter is the wrong time of year to be taking such photos as stingless bees are sensitive to colder temperatures (Sydney is about as far south as they range). Beekeeper Elke Haege has kindly agreed to let me photograph one of her nests when the weather is warmer, but in the meantime she has donated the photo below.
In it you can see that the interior layout is quite different from a honey bee nest. To the right are the more loosely structured pollen pots and honey pots (note the honey spilling out). There are 3 terraces of brood cells on the left, holding the developing larvae, with the topmost terrace at the top left corner. This top terrace has three uncapped brood cells at its edge, each awaiting its food store and an egg. I can’t make out the queen bee; she would have a much larger, paler abdomen.
There are about 500 species of stingless bees worldwide, mostly in the tropics, with 16 of them native to Australia. Stingless bees belong to the Melponine section of the Apidae family (which includes honey bees.) Of the Australian species, only the Tetragonula carbonaria in these photographs are sufficiently cold-resistant to range as far south as NSW. However the other species have generally similar habits. Some are called sweat bees because they occasionally lap human sweat for the liquid and salts in hot weather.
The term “sugar bag” goes back to early days. Gerry Wilkes’ Dictionary of Australian Colloquialisms lists an 1830 usage ‘Choogar-bag, choogar-bag’ (sugar bag) as being Aboriginal people’s English expression for honey, or anything sweet.
A fascinating social insect, and I’m looking forward to filling in more of the picture come spring!