Assassin bugs (Reduviidae) produce
venoms that are insecticidal, and which induce
pain in predators, but the composition and function of their individual
venom components is poorly understood. We report findings on the
venom system of the red-spotted assassin bug Platymeris rhadamanthus, a large species of African origin that is unique in propelling
venom as a projectile weapon when threatened. We performed
RNA sequencing experiments on
venom glands (separate transcriptomes of the posterior main gland, PMG, and the anterior main gland, AMG), and proteomic experiments on
venom that was either defensively propelled or collected from the proboscis in response to electrostimulation. We resolved a
venom proteome comprising 166
polypeptides. Both defensively propelled
venom and most
venom samples collected in response to electrostimulation show a
protein profile similar to the predicted secretory products of the PMG, with a smaller contribution from the AMG. Pooled
venom samples induce
calcium influx via membrane lysis when applied to mammalian neuronal cells, consistent with their ability to cause
pain when propelled into the eyes or mucus membranes of potential predators. The same
venom induces rapid
paralysis and death when injected into fruit flies. These data suggest that the cytolytic, insecticidal
venom used by reduviids to capture prey is also a highly effective defensive weapon when propelled at predators.