Singapore Ant

Description:

Pretty sure this is the correct ID. Someone please correct me if I'm wrong... (From PaDIL): Body length of workers (highly variable - Polymorphic) 1.8 - 3.5 mm. This ant is dark brown to blackish brown, and usually with a conspicuous yellow area mediobasally. A relatively large Monomorium species; Body yellowish brown to reddish brown from head to postpetiole; gaster blackish brown. Mandibles each with 4 teeth, the basalmost sometimes obscure. Eyes large, each with around 20 facets. Median paired carinae of clypeus obscure. Metanotal groove distinct. Propodeum with angulate posterodorsal border; the area of petiolar insertion carinate. Ventral outline of petiole less convex than in other species. Postpetiole 1.1 -1.2 times as long as broad. Mesopleuron and sections of lateral surfaces of propodeum with fine puncturation; dorsal surface of propodeum with transverse rugae.

Habitat:

Seems to be originally from India, but has become an invasive species across SE Asia, Austral-Asia, and even the Americas.

Notes:

I've noticed these guys on the tree in front of the bus stop at Sammakorn Villiage, eastern Bangkok, many many times. I believe they have a nest in the tree, as it is half dead. The tree appears to have been attacked by termites. Occasionally, I'll see these ants either moving their own larvae or larvae of other ants (can't tell).