Effect of Different Wave-length of Light under Long Day Condition During Incubation Period of Egg on Diapause in Silkworm, Bombyx mori L.

Abstract

To confirm a photorecepter in the embryo having a concern in embryonic diapause induction in next generation. First of all, effects of different wavelength on diapause formation in the silkworm, Bombyx mori, irradiated for 17 hr daily during incubation period of egg at 18-19°C, were examined with those races, J106 × Daizo and (w2 × Daizo) × W2.(1) It was found that lower light intensity limits for the production of moths laying diapause eggs were below 1.3 μW·cm-2 at the wave-length of both 483 nm and 503 nm, and between 0.0084 and 0.039 μW·cm-2 at 525 nm.(2) It was also found that higher limits for non-diapause eggs were beyond 13 μW·cm-2 at both 483 nm and 503 nm, and between 3.9 and 17.8 μW·cm-2 at 525 nm.(3) From the examination on the effects of light of wave-length from 356 nm to 687 nm at equal light intensities of 10 or 13 μW·cm-2, it became evident that longer wave-length than 640 nm had no effect upon the production of diapause eggs, likewise in darkness, while shorter wave-length than this showed a distinct effect upon it, as the white light did.