Classification: | Kingdom: Animalia | Phylum: Arthropoda | Class: Insecta | Order: Hymenoptera | Family: Formicidae | Genus: Pristomyrmex |
These ants are nursing scale insects found on the leaf of Syzygium grande (Sea Apple).
Besides the scale insects, this ant also farms leafhoppers, mealy bugs and aphids.
Dolichoderus bituberculatus is a synonym of Dolichoderus thoracicus according to the AntWed. This ant has been used as biological control agent to drive away mirid bug (Family: Miridae) from cocao tree (Theobroma cacao). Hence, it is known as Cocoa Black Ant.
In Singapore, this ant is common in deserted rubber tree plantations and usually appears in large contingent that march across all surfaces, low and high. When I started to pay more attention to ants in late 2012, this ant caught my immediate attention because of its abundance in a nearby park that has kept a small area of the old rubber tree plantation. I will never know when the ant started to roam this place. Over the years when I started my frequent walk in this park, it had taken over the territories previously occupied by the weaver ants and the yellow crazy ants over time. The weaver ants used to be the dominant ant species in the park which was a "pain" to me at times. Over several months, they had disappeared in most areas and retreated to a few trees at the fringe of the park. For a while, they used to petrol even on the walking track. Replacing them was this Cocoa Black Ant.
Though all the ants appear to be about the same size in most of the colonies seen, I did see larger ones occasionally.
The ant makes its nest by wrapping leaves on trees or in between leaves. The nest below was constructed in a leaf of a Portia Tree (Thespesia populnea). When the nest was disturbed, the ants rushed out of the nest from gaps around the nest, similar to the phenomenon seen with the Weaver Ant (Oecophylla smaragdina), in an attempt to defend the nest from the threat.
This nest was built in between 2 leaves: