The stingless honeybees revisited
On the 26th Ronny Willman visited Dokmai Garden and we discussed the native stingless bees I blogged about before. He said that a mutual Swedish friend, late Dr Josef Stark of the Swedish University of Agricultural Sciences, reported that in South America where the traditional honeybees (Apis spp) are absent from the native fauna, people do harvest honey from the stingless bees. This is done by gently removing the soil and then use a straw to suck up the honey from the eggcup-like honey cells. These are kept separate from the rest of the colony and so their harvesting would not harm the bees too much.
With this background we proceeded by gently excavating the Dokmai Garden wild stingless bee society, using spoons and straws. The bees did not seem to mind. Indeed there were many thumb-sized cells of a stiff material reminding one of the smooth crust of Chinese deep-fried foods or spring rolls. It was probably wax, but not soft, and the literature claims that the entrance funnel is made from ‘plant resin’ so the actual material remains a mystery.
We opened one cell and sucked the watery content. It was acid like vinegar! We opened another one, it was full of pollen with an equally acidic fragrance. Ronny speculated that maybe the bees conserve their pollen with acid, just like honeybees conserve their pollen with sugar, similar to making jam. If they do not do that, the harvest would be spoiled by moulds. He also remarked that honey is very acid (around pH 3.9), but we do not sense that due to the sugar content. Ordinary distilled white vinegar 5-10% has a pH of about 2.4-3.4. I could also sense a smell of ‘medicine’, like diethyl ether. We do not think the acidity was a mistake or due to an unwanted infection, because all cells were similar, they were sealed and the bees seemed prosperous.
Evidently, insects with a valuable food storage such as sweet honey need to defend themselves, like wild honeybees. Another way of keeping the food storage away from robbers like humans, bears and ants, would be to transform it into something we detest, i.e. acetic acid. Then an aggressive behaviour and stingers would not be necessary. This, and the fact scientists have observed native South Americans ‘sucking’ ‘honey’, implying it must be a liquid with a low viscosity, not traditional ‘honey’, makes me wonder if any stingless bee makes a sweet honey? We ask our South American readers to share their experience!
Whether the stingless bees transform the nectar into vinegar by using bacteria or yeasts in an oxidized environment, or whether they collect something else than nectar (decaying fruit juice?), or whether this is a seasonal phenomenon is unknown to us. Maybe our readers have more information?
In conclusion, this native Thai species of wingless bee (Trigona apicalis?) is not suitable for honey harvesting, at least not this time of the year. The stingless bees remain a curious part of your monsoon garden, important for pollination.
These cells were just extracted from the stingless bee society. To the right between the fingers is an opened cell exposing its treasure of pollen. For fun we placed that cell inside one of the domesticated bees’ hives to see if the honeybees would eat it. The other cluster of cells to the left shows open and closed cells, with vinegar and pollen. In order to keep the society alive we avoided affecting the larval chambers; we only investigated their food storage.
Text and Photo: Eric Danell