Abstract
In stinging Hymenoptera, the poison gland and its vesicle have been understood largely as sources of toxic, irritating, or antimicrobial compounds, which the sting injects into a target. However, external uses of poison gland secretions have also been reported: Pseudoneoponera (formerly Pachycondyla) froth a proteinaceous poison gland secretion into foam threads that entangle attacking ants, and Crematogaster smear opponents with a contact toxin generated on a spatulate sting from poison and Dufour gland products4. Here we report that workers of the myrmicine ant Lordomyrma azumai produce, in the poison vesicle, a secretion, likely proteinaceous, that solidifies upon extrusion into an adhesive thread. The sting is retained as the conduit, but the secretion it delivers is applied externally rather than injected, and acts as a structural material: workers wipe the thread onto opponents and tether them to the substrate. To our knowledge, no hymenopteran venom secretion functions as a solid thread; in the closest case, Pseudoneoponera3, the secretion entangles attackers as a foam rather than as a continuous solid filament.