Australian honeypot ants store a sugary liquid in their abdomen. © Danny Ulrich
Honey from honeypot ants has been known to Australian Aborigines for thousands of years as a food and medicine. A study now shows that ant honey actually works against numerous bacteria and fungi. Its chemical composition and its mechanism of action differ significantly from honey. From the researchers’ point of view, this could also make it interesting as an inspiration for new antibiotics.
Australian honeypot ants (Camponotus inflatus) have developed an unusual way of storing food supplies: When there is a lot of food available – including plant nectar and sugary excrement from aphids – some workers gorge themselves so much that their abdomens become swollen. Like filled honey pots, they then hang motionless on the ceiling of the anthill and are fed by other workers. If the supplies are needed, they regurgitate the sweet mass.
Traditional remedy studied
“Indigenous Australians hold honeypot ants in high regard because they are a rare source of natural sugar in an arid environment,” explains a research team led by Andrew Dong from the University of Sydney. “Apart from its use as a food source, there are records of ant honey being used to treat sore throats and colds.” This aspect intrigued Dong and his team. Antimicrobial properties have already been proven for bee honey. Does ant honey have a similar effect?
To find out, the researchers collected honey ants in the former gold mining town of Kurnalpi in western Australia. They were assisted by Danny Ulrich, a local guide from the Tjupan Aboriginal people. “Honey ants are more than just a food source for our people. Digging for them is a very convenient way of life and a way to bring the family together,” he says. “Our people have enjoyed the sweet honey ants for thousands of years. As for medicinal use, we use it for sore throats and sometimes as an ointment to keep infections at bay.”
Significant antimicrobial activity
Dong and his team analyzed the chemical properties of the honey produced by the ants and tested its effectiveness against various bacteria and fungi in several experiments. “Our research shows that honeypot ant honey has a special effect that distinguishes it from other types of honey,” says Dong’s colleague Kenya Fernandes. Among other things, the ant honey had a strong effect against bacteria of the Staphylococcus aureus species as well as against the mold Aspergillus and the yeast fungus Cryptococcus. All three can cause serious human infections.
Compared to therapeutic honeys such as jarrah and manuka honey, the researchers found that ant honey appears to work through other, previously unknown mechanisms. In addition to other antimicrobial active ingredients, bee honey often contains a lot of hydrogen peroxide and thus kills pathogens. In ant honey, on the other hand, the hydrogen peroxide content was low. “This suggests that a significant portion of the activity is likely due to unique non-peroxidic mechanisms,” the team writes. Fernandes explains: “This discovery means that ant honey may contain previously unknown compounds with significant antimicrobial activity; identifying these compounds could provide us with starting points for the development of new types of antibiotics.”
Therapeutic Honey
In addition, the researchers examined the microbiome in the digestive tract of the food-filled honey pot ants. They found that individual bacterial and fungal species dominated. At the same time, however, other bacteria and fungi were also detected in significantly smaller proportions, including molds of the Penicillium genus. The antibiotic penicillin comes from fungi of this genus.
“Our results indicate a possible link between the microbiota and the health of the insects, which in turn could influence the properties of the honey,” the research team writes. “Overall, our study shows that expanding research on therapeutic honey to other honey-producing hymenoptera can provide valuable insights and should be encouraged to better understand this medicinally and economically important commodity.”
Source: Andrew Dong (University of Sydney) et al., PeerJ, doi: 10.7717/peerj.15645