Embryonic Development in Multivoltine Silkworm, Bombyx mori L. Observed by Stereo Microscopy and Scanning Electron Microscopy

Abstract

Embryonic development in Bombyx mori L. in three multivoltine silkworm strains, Nangnoi, Khakii and Samrong, were observed by stereo microscopy and scanning electron microscopy from day 1 after oviposition until one day before hatching. Nangnoi, Khakii and Samrong strains entered reversal stage 4 to 4.5 days after oviposition and showed ocellus, setae and spiracles on 5 to 6 days. On 7, 8 and 9 days or on 10 days, embryos were apparently observed. After head-abdominal pigmentation, the embryonic development in Khakii and Samrong strains was completed in 9 days while Nangnoi was in 10 days. In addition, SEM micrographs in Samrong strain obviously showed external morphology of the embryo.