The phenomenon of “exploding ants” is a form of defensive behavior known as autothysis (from the Greek for “self-sacrifice”). This is not a voluntary action but a highly specialized, last-resort defense mechanism. When threatened by a predator or rival insect, these ants contract their abdominal muscles with such extreme force that their body wall ruptures, tearing them apart and releasing a toxic, sticky, or corrosive substance stored in their oversized mandibular glands. This act sacrifices the individual to protect the entire colony.
The most well-studied species is Camponotus saundersi, a type of carpenter ant found in Southeast Asia. These ants have massively enlarged mandibular glands that run the entire length of their bodies. These glands are filled with a toxic, sticky secretion. When a worker ant is engaged in a fight it cannot win—often with other social insects like ants or termites—it will latch onto the opponent and violently rupture, releasing the glue-like toxin that immobilizes or kills the threat.
More recently, a large group of exploding ant species was re-discovered and classified under the Colobopsis cylindrica complex, also in Southeast Asia. This group showcases a fascinating caste system within the exploding defense. The minor workers are the ones that perform autothysis. Their mandibular glands are filled with a bright yellow, corrosive, and foul-smelling chemical cocktail that they burst to spray onto a threat, effectively creating a “chemical wall” to block invaders from the nest entrance.
Within the Colobopsis cylindrica group, the defense is two-tiered. The colony’s entrance is first guarded by a class of major workers known as “doorkeepers.” These ants have perfectly plug-shaped, enlarged heads. When the nest is threatened, they use their heads to physically block the entrance, forming a living barricade. If an intruder manages to bypass this physical barrier or attack the doorkeepers, the smaller minor workers then swarm out and deploy their suicidal explosive defense.
Types of Ants That Explode
Colobopsis explodens
Colobopsis explodens is the most well-known “exploding ant,” native to the rainforests of Southeast Asia, particularly Borneo and Thailand. When threatened, worker ants sacrifice themselves by rupturing their bodies, releasing a sticky, toxic yellow secretion that immobilizes or kills intruders. This act of self-destruction, known as autothysis, protects the colony from predators such as invading insects or other ant species.
Colobopsis saundersi
Discovered in Borneo, Colobopsis saundersi is the first recorded species of exploding ant, identified in the early 20th century. When enemies attack, this ant contracts its abdominal muscles so powerfully that its body wall ruptures, splattering a corrosive fluid stored in enlarged glands along its sides. The substance glues the attacker in place and releases a defensive odor, saving the colony even at the cost of the ant’s life.
Colobopsis cylindrica
Native to Malaysia and nearby regions, Colobopsis cylindrica is another species capable of explosive defense. Its sticky secretion is yellowish and can spread widely, affecting multiple attackers. The fluid contains toxic compounds that deter or kill smaller predators like spiders or other insects. Its suicidal strategy ensures colony survival in competitive tropical ecosystems.
Colobopsis leonardi
Found in Indonesia, Colobopsis leonardi workers are known for their aggressive defensive behavior. They use their explosive ability mainly during territorial conflicts. The self-sacrificial detonation releases a resinous chemical that is both adhesive and irritating, effectively halting enemies in their tracks.
Colobopsis badia
This species is commonly found in the humid forests of Thailand and Malaysia. Colobopsis badia exhibits controlled self-rupture when directly attacked. Its secretion serves as a dual-purpose defense—sticky enough to trap smaller arthropods and toxic enough to repel larger aggressors.
Colobopsis corallina
Known from Bornean forests, Colobopsis corallina displays similar behaviors to its relatives but has a unique secretion color and odor, adapted to its specific environment. The chemical compounds vary between species, possibly depending on local predator types and ecological pressures.
Colobopsis sp. “Yellow Goo”
This unnamed or undescribed Colobopsis species from Borneo gained the nickname “Yellow Goo” for its brilliant defensive secretion. Field researchers observed that when disturbed, the workers simultaneously explode, forming a defensive barrier of sticky fluid around the nest.
Colobopsis paradoxus
Native to parts of Sumatra, Colobopsis paradoxus has been observed using its explosive defense sparingly, often as a last resort. The chemical substance it releases is believed to have evolved to target specific predator insects such as weaver ants and small parasitic wasps.
Colobopsis dentata
This lesser-known species from the Malay Peninsula has smaller workers but potent glands. When disturbed, several ants will simultaneously rupture to repel invaders, forming a defensive wall of toxic material that protects the colony entrance.
Colobopsis truncata
Unlike its relatives, Colobopsis truncata not only uses explosive defense but also employs its truncated head to block the nest entrance, a behavior known as “phragmosis.” This ant’s dual defense strategy makes it one of the most specialized among the exploding ants, balancing physical defense with chemical sacrifice.