Tetraponera rufonigraTetraponera rufonigra, tuntud ka kui kahevärviline puumardikas, on kodumaine Lõuna- ja Kagu-Aasias. Neid võib leida Indoneesiast Indiasse. Need sipelgad on leidnud ainulaadse niši nii looduslikus kui ka inimese poolt mõjutatud keskkonnas.

Tetraponera rufonigra are typically found nesting in hollow tree branches, wooden structures, or even bamboo. Highly adaptable, they favor sunny forest edges and occasionally make themselves at home in the wooden beams of old houses.

The entrance to their nests is usually a small hole, allowing only a worker ant to pass through—a defense tactic against intruders.

These medium-sized ants have a striking appearance with a black head, red thorax, and black abdomen, giving them their distinctive bicolored look. Agile and quick, the worker ants possess excellent eyesight, enabling them to react swiftly to movements and even jump if necessary.

Colonies are typically monogynous, housing 300 to 500 individuals, though some larger colonies may reach up to 1,000 ants. There are occasional reports of polygynous colonies with multiple queens. The queen can live up to 15 years, tirelessly laying eggs, which workers nurture into pupae and, eventually, into adult ants. Interestingly, researchers have yet to determine why some larvae develop cocoons while others remain exposed.

Tetraponera rufonigra ants are known for their aggression, especially toward other ant species. They actively hunt small insects using their stinger, with a sting comparable to that of a wasp. Dead insects also make a tasty meal, often brought back to the nest through impressive teamwork.

For example, dragging a cricket leg into the nest can become a collective effort, sometimes requiring creative solutions like cutting it into smaller pieces for easier transport. Once the ants are done with their feast, they toss the remains out of the nest, keeping their surroundings clean. Even discarded bits on the forest floor are reexamined to ensure no nutrients are wasted.

Their diet includes proteins, sweet plant sap, nectar, honeydew from aphids, and other sugary substances. They also maintain vital symbiotic relationships. For instance, they protect acacia trees by eliminating parasites and scaring off larger mammals, while the trees provide them with shelter and food. Similarly, their association with Rhizobiales bacteria helps them absorb crucial nutrients like nitrogen.

Scientific studies have highlighted variations in the physical traits of T. rufonigra, particularly in their midsection and narrow waist. Additionally, isolation from their colony increases their aggression levels over time, likely due to the loss of their pheromonal “identity.” This leads to hostility even toward their own kind—a fascinating but puzzling behavioral adaptation.

Tetraponera rufonigra exemplifies the complex and intricate lives of ants. From their unique nesting habits to their aggressive hunting tactics and symbiotic relationships, these ants continue to intrigue researchers and nature enthusiasts alike.