Researchers at the University of Queensland in collaboration with Queensland Health Forensic and Scientific Services have uncovered the secret of trehalulose — a sugar that is only produced by the tiny insect and does not spike blood glucose levels when eaten.
Nectar sugars are largely glucose, fructose, and table sugar (sucrose), not trehalulose, so the question became "were the bees finding it or making it?"
Scientists discovered the rare healthy sugar unique to native stingless bee honey in 2020
The bees make it in their gut after consuming nectar high in sucrose
Researchers are now hoping to identify crops with high sucrose nectar to increase production
"We fed stingless bees some sugar solutions to try and find out the origin of trehalulose," UQ organic chemist and research leader Dr Natasha Hungerford said.
"Then we took two different solutions and fed them to a small colony of bees that were confined for a short amount of time, 24 hours, and we fed them sucrose or table sugar.
We found that when we analysed the honey that they produced in that short amount of time [they had] transformed the sucrose into trehalulose.
"So there's no sucrose left, which was pretty remarkable, really."
Because of the unique way the Melipona Stingless bees stores its honey — in small pots made from a mix of beeswax and tree resins — the researchers looked at a number of potential sources for the special sugar, like native trees and other things in the environment.
"What we found is that stingless bees have a unique capacity to convert sucrose to trehalulose and produce honey rich in trehalulose in their gut," Dr Hungerford said.
Feeding the bees glucose and fructose did not produce the same result, allowing the researchers to narrow in on sucrose.
"What this tells us then is that if the bees are sourcing nectar that ties in sucrose from the environment, then they'll produce the honey that's high in trehalulose with the added health benefits," Dr Hungerford said.
Going with their gut
Stingless bees are found throughout tropical and subtropical parts of the world, but produce significantly less honey than the larger European honey bees that provide the bulk of the product on supermarket shelves.
Their honey is highly prized as a specialty food, is considered medicinal in Indigenous cultures, and attracts a high price.
Even though it is a favoured product, and with the health benefits, the hives produced less than a kilogram a year and they need some of the honey themselves," Dr Hungerford said.
"In warmer climates, they tend to produce excess honey, whereas in cooler areas they might only produce what they need for themselves."
Dr Hungerford said the syrup produced in the experiment is not considered honey because it did not come from nectar.
"The honey we produced in the lab is, in fact, fake honey, and we were able to distinguish it from natural honey by isotopic testing," she said.
"This trehalulose-rich syrup that was produced might be considered a potential secondary product of stingless bees, but it is not honey.
"Stingless bee honey is fairly rare, people quite often consume their own supplies," Dr Hungerford said.
"There are some people that sell it and it does get quite a high price. It's usually sought after by high-end restaurants as a unique flavour to add to their dishes.