Surprising use of tools by predatory insects

Europa Press

La Jornada Newspaper, Friday, May 16, 2025, p. 6

Madrid. Tool use has been widely documented in a wide range of species in the animal kingdom, primarily among vertebrates, and now a notable example has been added in the world of insects.

Researchers from China Agricultural University, Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences, and the Institute of Zoology have described how the assassin bug, Pahabengkakia piliceps ( P. piliceps ), uses resin from the nests of stingless bees to lure them into the predator’s optimal hunting position. This is the first comprehensive evidence of an invertebrate predator using tools to exploit the collective defenses of social insects.

Stingless bees deposit a sticky, pungent resin around the entrances to their nests to deter intruders. When predators like ants or geckos become trapped, guard bees swarm to immobilize them. But assassin bugs use this defensive mechanism against bees.

Researchers observed that the assassin bug deliberately collects resin with its front and middle legs to cover them with the sticky material. The resin's amplified chemical signal attracts guard bees to the assassin bug's location. In this way, the resin not only doesn't repel the predator, but acts as a beacon, drawing the bees within striking distance.

This is a sophisticated manipulation of prey behavior , said Wang Zhengwei of XTBG. The bug not only avoids detection, but actively provokes attacks to create opportunities .

Through controlled field trials, the researchers showed that resin-coated assassin bugs achieved a predation success rate of 75 percent. This rate dropped to less than 30 percent for resin-free bugs. Critically, they found that applying resin to non-hunting body parts (e.g., the abdomen) also offered a relative benefit, confirming that resin viscosity was not the key to predatory success. Instead, chemical analyses revealed that the insects' handling of resin increased emissions of volatile compounds, which are irresistible to protective bees.

As a specialized predator, P. piliceps is completely dependent on stingless bees for its survival and reproduction. This dependence likely drove the evolution of its unique tool-using behavior among predatory insects to improve their hunting efficiency, indicating a link between tool use and dietary specialization across the animal kingdom.

The study challenges assumptions that complex tool use requires advanced cognition, highlighting how ecological specialization can shape seemingly intelligent behaviors. “Unlike vertebrates, insects like P. piliceps offer a practical system for exploring the evolution of tool use in animals,” Wang said.