These ants are casually called "exploding ants". The poisonous substance that is oozed by the workers during the "explosion" is not only disastrousfor the invader, but also for the worker itself: It dies just as the attacking insect, even if the latter is bigger than the worker.
The scientists regularly travel to Borneo for research purposes. It is especially remarkable that this act of self-defence does not only occur in immediate proximity of the own nest. The researchers could also observe this behaviour at a larger distance. It is presumed that the workers also want to defend their source of food, which is a particular biofilm on leaves.
Irina Druzhinina, affiliated to the Vienna University of Technology and Principal Investigator in the WWTF-funded project "Voluntary Self-Sacrifice in Exploding Ants: a mechanism to defend co-evolved microbiomes?" (LS13-048) investigates the leaf surface as well as the stomach contents of the ants in tha laboratory. The researchers hope to find fungi and bacteria in the ants' micorbiome which can decompose cutin (a kind of wax that covers plant surfaces) and even synthetical polymers. In the future, this could lead to an approach for the natural decomposition of plastic waste.
Here you can read more about this project (in German).