Photo 1: An army of fierce Fire Ants on the march, they can be seen
crossing roads in the late evening on the way to a raid or at dawn
when they are returning with their loot.
Anyone who's lived in rural areas (farms, plantations) or camped in the forest in Borneo would very likely have had painful (very painful) encounters with this species of large agressive ants. At least I can say that for myself having been bitten and stung countless times. Luckily, for me at least, the pain from these stings though very painful did not have lasting effects but soon subsided without any swelling or other complication.
Photo 2: Stepping on a line of these marching ants would
mean inviting trouble and a taste of their "fire" and viciousness.
These ants are nocturnal and form huge raiding swarms especially on wet nights that attack any living or dead creatures that they come across, invading houses and killing insects, geckos and even chickens (in coops where they cannot escape) as well as carrying off leftovers from the kitchen. Big preys like birds and lizard are overwhelmed with their stings and cut alive and carried in pieces back to their nest. They are strictly carnivorous so your vegetables would be safe.
Photo 3: An unfortunate house gecko (cicak) being smothered
by a swarm of fire ants which will soon rip it apart and carry
back to their nest in small pieces.
I have seen even large chickens and whole broods of chicks locked up in the "kandang" by their owners killed by these ants. At dawn all that were left were heads, bones and some feathers. The chickens would be lucky if the noise they made could rouse their owners to save them. People would rush out sleepy-eyed from their house with hot water or oil or if available, cans of insect spray to defend their livestock. Usually letting let their chickens out would be enough to let them escape this slow cruel death.
These ants belong to the genus Leptogenys in the subfamily Ponerinae (Order Hymenoptera) and were given the name "Danum Fire Ants" by Dr Arthur Chung in his book "Common Lowland Rainforest Ants of Sabah". Although they are found in many places in Sabah and presumably elsewhere in Borneo, Dr Chung probably had most of his experiences with this species in the Field Studies Centre in Sabah's Danum Valley!