This short observation was filmed on Nov 23rd 2016 in Bukit Timah Nature Reserve, Singapore. Malaysian giant forest ant (Dinomyrmex gigas) is a central place forager. The colony structure is described as polydomous. Workers communicate efficiently and recruit effectively to optimize foraging yield. Large workers have evolved ergonomy to be self-sufficient in most tasks. Its diet is mostly honeydew and excrements but can also prey on insects.
These ants have been reported to have up to 14 subterranean nests and control a three dimensional forest canopy territory covering about 0.8 ha. Workers are of two types. The smaller minors (~175 mg) are roughly half the size of the larger (~375 mg) majors. They forage at night in the forest canopy in very large numbers. Only during day time very few workers forage on the forest floor and this individual is one of them. The reduced number of daytime workers could be an avoidance strategy against Phorid flies parasitizing ants. Malaysian giant forest ant is famous for their “ritual fights” where workers do a boxing movement with their front legs. These intraspecific between colony fights take place on territorial boundaries among specialist major workers. These ritual fighters can meet repeatedly at the same spot. Fights can last very long time for many days and even months. Colonies establish “barrack” nests on the periphery of their territories where long-term conflicts occur. Interspecific conflicts almost always end up deadly.
In terms of behavior and niche this ant has many convergent similarities with another giant (in fact the Worlds largest) arboreal and called the Bullet Ant (Paraponera clavata). Bullet ants have a powerful bite and can sting very painfully. The workers are so big that when they move from one leaf to another the leaves bend under their weight as you can observe from the following video showing a worker patrolling on a piper plant at La Selva Biological Field Station in Costa Rica. Like the Malaysian Giant Forest Ant, the Bullet Ant workers are specialized on plant nectar. This foraging individual makes a few repeated stops to check out the water droplet hanging on the very tip of a petiole. Curiously, while patrolling she appears to ignore a planthopper (Hemiptera) feeding on the sap of the plant:
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