Analyses of Metal Ions in Spider Venoms in Relation to Insecticidal Activity of Clavamine

Abstract

To elucidate insecticidal activity of spider toxins, metal ions in venoms and in the bodies were determined by thin layer chromatography, spark source mass spectrometry, ion chromatography, inductively coupled plasma emission spectrometry and atomic absorption spectrometry. Two kinds of spiders were used, Nephila clavata and Nephila maculata. Metals from their venom glands were extracted with hydrochloric acid and the metal concentrations were almost the same in the two species. Many kinds of metals, Fe, Zn, Pb, Cu, Ca, Mg, Na, P and S were found at higher levels in the venoms at concentrations higher than in the bodies. The contents of metal ions were low in the dragonfly and the cicada which are considered to be preys. Clavamine, the main insecticidal component in N. clavata, was effective on larvae of a mosquito with Ca²⁺, Fe³⁺ or Pb²⁺, but ineffective with Mg²⁺, Zn²⁺, Fe²⁺ or Cu²⁺. It is suggested that the metal chelates play an important role in the intoxication and detoxication of the spider toxins.