Macrotermes carbonarius is the only open foraging Macrotermes species and also the only black species, that I know of. It is found in South East Asia and parts of Indochina, but its range is patchy and it is only locally abundant. This means where it occurs, it is common, but where it is not found, there is no trace of them, even over vast swaths of what would be considered suitable habitat. It mainly occurs in lowland rainforest areas, but can be found in crop/agricultural plantations.
This is a large termite species and can attain 18-19 mm in length – for the major soldier (measured from mandibles to abdomen). As in most Macrotermes sp, there is dimorphism for both workers and soldier castes (two sizes).
Macrotermes carbonarius forages mainly at night and occasionally during the day, up till early afternoon, depending on the surrounding environment and weather. In exposed areas, they will rarely emerge during daylight hours. On rare occasions, I have observed them foraging in late afternoon (around 4 pm), but this has to be in a shaded area.
The major workers fan out from subterranean tunnels, moving in columns to specific locations to chew up dead leaves, grasses, twigs, branches, and any other relatively soft plant matter. They do not attack human made structures nor trees. Foraging locations are not fixed, and changed daily in most cases. While Macrotermes carbonarius builds large mounds up to around 2 meters high, a major proportion of their nest (and population) is located below ground level. Their mound walls are extremely thick in most places, and used to house their fungus gardens and nurseries.
As one would expect for an open air forager, Macrotermes carbonarius soldiers are aggressive, and readily rush out to confront any intruders if their nest or foraging columns are disturbed, just like ants would. This behavior is actually more akin to ants, rather than termites, as most termites are shy and adopt passive defense methods. Their soldiers can deliver a painful bite with their large mandibles, but they do not sting (no termites sting), unlike many types of ants.
(Above) Macrotermes carbonarius termites with all the castes
(Above) Major workers of the termite Macrotermes carbonarius
(Above) Macrotermes carbonarius minor worker, which is paler and smaller than the major workers
(Above) M. carbonarius minor soldier
(Above) A major soldier of the termite Macrotermes carbonarius
(Above) Macrotermes carbonarius major soldiers
(Below) A trail of Macrotermes carbonarius on the ground. Nests will open exit holes quite a distance away from their mound to forage. Once foraging is done, these holes are sealed.