Photograph by Design Pics Inc.
The geographic cone snail, Conus geographus, is the most venous cone snail, and one of the most venomous animals on the planet; human fatality rates are as high as 65%, from doses of 0.038-0.029 mg/kg.
While some cone snails feed rapidly by impaling prey with harpoon-like teeth that deploy this venom, others feed by extension of a distended ‘false mouth’ acting as a feeding net. This is a slow process, limited in its effectiveness as prey fish must be unaware of the cone snail’s presence, or chemically sedated, to ensure their capture.
Discovery of specialised insulins in the venom complexes of Conus geographus and its congener Conus tulipa, in a study published by Safavi-Hemami et al. in The Proceedings of the National Academy of Sciences on January 20th, is thought to supply such sedation. When injected into fish, the venom and insulin together elicit hypoglycemic shock, a condition characterised by dangerously low blood glucose, which immoblise the fish and allow it to be captured more easily. The fish appear almost passed out, or drunk.
This reaction mixture has been named the ‘nirvana cabal’, and it is thought that the release of the combination of these toxin venoms into the water column could allow entire schools of fish to be simultaneously captured with little effort.