Induction of Precocious Adult Eclosion by the Eclosion Hormone Extracted from the Heads of Bombyx mori (Lepidoptera : Bombycidae) and Samia cynthia ricini (Lepidoptera : Saturniidae)

In order to compare the eclosion hormone activity between two different species of lepidoptera, eclosion hormmone (EH) extracted from adult heads of Bombyx mori or Samia cynthia ricini was subjected to the bioassay to induce precocious adult eclosion. By performing reciprocal injection of the EH in both species, the authors demonstrated that Bombyx crude EH can induce the precocious eclosion of the pharate-adult of the Samia, while Samia crude EH has the same effect to the pharate adults of Bombyx. The hormonal activities were not reduced throughout the several purification steps in both cases. Necessary amount of EH to induce the precocious eclosion in more than 50% of the assayed pharate-adults of Bombyx mori was equivalent to 3 heads in Bombyx and dquivalent to 2.5 heads in Samia. The results may suggest that eclosion hormone is not species-specific, so far as two lepidopteran species used in the present experiments are concerned.