Most ant species use their stingers to inject venom or other toxins into prey and threats. Lordomyrma azumai, a relatively rare species found in Japan, appears to use its stinger differently: workers release a substance that forms a thread and traps intruders in place.
The behavior is described in a study published as a preprint on bioRxiv. The substance has not been identified, though the researchers suggest it is probably protein-based. According to the study, it solidifies when exposed to air.
Lordomyrma azumai was discovered and described in the 1940s, but has not been studied in depth. The new finding offers an initial glimpse of how the ants defend their colony, while leaving key questions unanswered, including what they do after immobilizing an intruder and whether the thread is toxic as well as sticky.
The researchers point to Crematogaster ants as a comparison: these ants spread venom with a spatula-shaped stinger, and the venom can form a toxic foam on contact with air. But the study says that, to the authors’ knowledge, no other hymenopterans—including ants, bees and wasps—are known to produce a solid thread this way.
Lead author Hajime Sasaki said the secretion can effectively glue an intruder to the ground, making it a useful defense even if it is not poisonous. Determining whether it contains toxins will require further experiments and analysis of the substance.
Sources: Focus.it.