In recent years, there has been growing interest in the medicinal value and antimicrobial activity of honey, especially in light of the rise in antibiotic resistance. While honey is typically produced by honey bees, other insects such as stingless bees, wasps, and ants can also produce honey-like substances from plant nectar. One such insect is the honeypot ant Camponotus inflatus, found in the central desert region of Australia. Researchers wanted to investigate whether this ant’s honey could have medical uses.
Their study, published in PeerJ, revealed that the honeypot ant honey has potent antimicrobial effects, particularly against heat-tolerant yeasts and molds that are resistant to most current antifungal drugs.
Honeypot ants are social ant species that build large nests in the soil. Within these colonies, certain worker ants called “repletes” serve as living food stores. These repletes are fed by other members of the colony who gather nectar and honeydew from the environment. The repletes store a golden honey-like substance in their flexible abdomens and become so full of honey that they are almost immobile. They hang together from the nest ceiling, forming an ant pantry. When other worker ants need honey, they visit the repletes and stimulate them to cough up some honey, which is then distributed throughout the colony.
Honeypot ants are mainly found in dry environments and have evolved their unique lifestyle multiple times due to its success. In Australian Indigenous culture, Camponotus inflatus holds cultural and nutritional significance. There are reports of traditional use of honeypot ant honey for treating ailments like colds and sore throats, as well as a topical ointment to prevent infections.
To further investigate the antimicrobial properties of honeypot ant honey, researchers obtained honeypot ant repletes and collected their honey. They compared this honey to well-studied bee honeys with antimicrobial properties, such as manuka honey from New Zealand and jarrah honey from Western Australia. The results showed significant differences between the honeypot ant honey and the bee honeys. While both bee honeys had broad antimicrobial activity, the honeypot ant honey showed remarkable potency against certain microbes but little effect on others.
The high sugar and low water content of bee honey contribute to its antimicrobial power by dehydrating microbial invaders. Honeypot ant honey had a higher moisture content, which could support the growth of some microorganisms. Additionally, most bee honeys contain enzymes that produce hydrogen peroxide, an antimicrobial compound. However, the honeypot ant honey retained its activity even after removing all the hydrogen peroxide. The researchers believe this unique antimicrobial activity is likely due to proteins or peptides derived from the honeypot ant.
In the natural environment, animals, plants, and their products are exposed to a wide range of microorganisms. Honey is an attractive food source for these microbes and must be protected to prevent spoilage and invasion by mold. The honeypot ant honey was particularly effective against tough pathogens that are well adapted to living in soils and dry conditions, which can cause severe infections in individuals with weakened immune systems. The researchers suggest that the evolutionary pressure from these soil microorganisms has resulted in the potent antimicrobial activity of honeypot ant honey.
The study’s findings support the traditional medicinal use of honeypot ant honey by Australian Indigenous communities and provide new insights into the relationship between honeypot ants, their environment, and the antimicrobial activity of their honey. While it is not feasible to domesticate honeypot ants for honey production due to their cultural significance and challenges with rearing them on a commercial scale, the honeypot ant honey may offer valuable insights for the development of new antimicrobial peptides. These peptides could help expand the arsenal of effective antibacterial and antifungal treatments needed to address emerging healthcare challenges.
