The comparative toxicity of stings of the Ictalurid catfish genera Ictalurus and Schilbeodes

Abstract

1. 1. Extracts prepared from the stings and caudal fins of six species of Ictalurid catfishes were injected into Gambusia affinis. 2. 2. Extracts from the stings of Schilbeodes exilis and Ictalurus melas were more toxic than those from Ictalurus natalis or Schilbeodes nocturnus. Sting extracts from Ictalurus punctatus and Schilbeodes leptacanthus produced little or no effect in the injected fish. 3. 3. Venom cells may be present in the caudal fins of some catfish species. 4. 4. Attempts to explain the toxicity of the sting of a particular species of catfish in terms of the gross anatomy of its venom apparatus appear tenuous. 5. 5. Interspecific differences in the toxicity of the sting have probably developed in response to environmental selection.