Recent studies by entomologists reveal that the carpenter ant, the largest genus in the subfamily Halinaciinae of Formicidae, produces a variety of previously unknown venomous peptides with potent antifungal properties. This discovery challenges the long-standing belief that older ants depend solely on formic acid for their defense mechanisms.
Analysis of Camponotus nicobarensis venom. Image credit: Koch et al., doi: 10.1126/sciadv.aed4078.
The Formicinae subfamily is renowned for its diverse ant species and ecological success, primarily known for producing toxins rich in formic acid, sometimes comprising up to 70% of their chemical defenses.
Interestingly, unlike many ant species, Gyricin ants lack stingers. They deliver venom through an acidopore located at the tip of their abdomen, which allows them to smear it on predators, spray it from a distance, or apply it to areas afflicted by bites.
Research has established that these venoms serve a multitude of functions beyond mere combat. Formicinae ants utilize their venom as an external immune defense, distributing it throughout their colonies to acidify their guts and create beneficial microbial communities, as well as for alarm signals and recruitment.
Traditionally, scientists attributed most of these functions to formic acid, believed to constitute the majority of the venom’s composition.
However, earlier studies suggested the existence of unexplored peptide compounds within the venom.
“We revisited some lesser-known publications from decades ago,” stated Professor Timo Niedermayer from the Free University of Berlin.
The earlier paper pointed out that these venoms contained peptidic compounds.
“Our investigation of the venoms from eight geographically distinct carpenter ant species revealed 35 peptides, known as formicytoxins, derived from two gene families.”
“While the specific formicytoxin profile varied among species, we found that its presence was widespread.”
“This indicates that carpenter ant venom is far more complex than previously thought.”
For this study, researchers employed cross-disciplinary methods, integrating biology, chemistry, and pharmacy.
By utilizing proteotranscriptomic techniques, they analyzed protein and RNA data from the venom and related tissues to identify distinct peptides and their corresponding gene sequences.
They also performed chemical analyses, conducted bioactivity tests, and synthesized formicytoxin in laboratory environments.
The findings suggest that these peptides play a crucial role in maintaining hygiene within ant colonies.
As ants distribute this toxin within their nests, the researchers theorized that formicytoxin may enhance and sustain external immune defenses long after the immediate antibacterial properties of formic acid have lessened.
“Certain peptides exhibit significant antifungal characteristics,” explained Dr. Simon Tragast, a researcher at Martin Luther University Halle-Wittenberg.
This is particularly pertinent given the threats posed by environmental microorganisms and pathogens to social insects like ants, as well as the escalating issue of microbial resistance affecting human health.
The Formicinae subfamily comprises over 3,700 species, indicating a significant potential for uncovering more bioactive compounds.
Explore the full study published in the journal Science Advances.
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Lucas Koch et al., 2026. Beyond formic acid: Peptides in carpenter ant venom help protect against disease. Science Advances 12(20); doi: 10.1126/sciadv.aed4078
Source: www.sci.news
