Tool use aids prey-fishing in a specialist predator of stingless bees

Tool use is widely reported across a broad range of the animal kingdom,
yet comprehensive empirical tests of its function and evolutionary drivers
remain scarce, predominantly focused on a few relatively intelligent
vertebrate lineages. In this study, we provide a comprehensive examination
of tool use behavior in the assassin bug Pahabengkakia piliceps, a
specialist predator of stingless bees that exploits resin droplet from bee
nest entrance to facilitate hunting. Field behavioral experiments
demonstrated that resin use is critical for hunting success, as the
predator uses resin to stimulate the colonial defense of stingless bees,
luring attacking bees toward its optimal hunting position. Chemical
analysis revealed that resin processing by the assassin bug enhances the
emission of volatile compounds, making the resin more attractive and
stimulating to guard bees. Through these experiments, we empirically
demonstrate how an invertebrate predator adapts to the colony defense of
social insects via tool use behavior. We further propose that complex tool
use can evolve under selective pressures driven by diet specialization.
Our findings offer a new model for studying the adaptive functions and
underlying mechanisms of tool use behaviors in animals.