Classification: | Kingdom: Animalia | Phylum: Arthropoda | Class: Insecta | Order: Hymenoptera | Family: Formicidae | Genus: Dolichoderus |

There are wide varieties of bugs, either their nymph or adult forms that will attract ants. The ants protect the bugs from their predators and in return, the bugs produce sugary excretion that benefit the ants.

These ants were nursing scale insects found on the leaf of a Sea Apple tree (Syzygium grande).

The scientific name Dolichoderus bituberculatus whic I used in the past was a synonym of Dolichoderus thoracicus according to the AntWeb. This ant had been used as biological control agent to drive away mirid bug (Family: Miridae) from cocao tree (Theobroma cacao) [1]. Hence, one of its common names was Cocoa Black Ant.

In Singapore, this ant was common in nature parks or reserves and usually appears in large contingent protecting certain bugs including their nymphs or in long marching column. 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 which had preserved some wild areas from an old Rubber Tree plantation. Over the years when I frequent this park, I observed that this ant had gradually taken over the territories previously occupied by the Weaver Ant and the Yellow Crazy Ant. It had even landed in my potted plant area since June 2015 supported mainly by the scale insects on the Cow Pea (Macroptilium lathyroides) plant. Around March 2016, for unknown reason, the ant simply disappeared without a trace from the park. About a year later in May 2017, they began to re-appear in the park in small numbers.

Reference:

[1] Khoo KC, Ho CT. The influence of Dolichoderus thoracicus (Hymenoptera: Formicidae) on losses due to Helopeltis theivora (Heteroptera: Miridae), black pod disease, and mammalian pests in cocoa in Malaysia. Bulletin of Entomological Research 1992; 82(4):485-491. | Read abstract |

Though the size of the ants appeared to be similar in most of the colonies seen, I did see larger ones occasionally.

The ant constructed its nest above ground level, usually on plants. Judging from the different shapes of their nests observed so far, it was likely to be opportunistic occupation of shelters or nests built by other insects or by taking advantage of existing structures. One of the nests shown below was wrapped in a leaf of a Portia Tree (Thespesia populnea), which I suspect may belong to the Weaver Ant (Oecophylla smaragdina) previously. One was constructed between 2 leaves (Suregada multiflora) that were in close proximity. The last one was in a deformed leaf of Heritiera littoralis.