Embryonic Development of Attacus atlas L. (Lepidoptera: Saturniidae)

Abstract

Attacus atlas was one of wild silkworm species that has been developed in Indonesia as an alternative silk source to domestic silkworm Bombyx mori. A. atlas was spread in tropical and subtropical rain forest and can be found almost in entire Indonesian islands. It has complete metamorphosis stage, including egg (embryo), larvae, pupa, and imago (adult). Embryogenesis was an important stage to know the physiology characteristic of insect such as diapauses. The research aimed to know the embryogenesis of A. atlas. The observation of embryonic development was done in two ways, observation within the eggshell and without the eggshell. The embryogenesis in A. atlas was done in seven days. Morphological observation on A. atlas embryo can be divided as pre-organogenesis and organogenesis stage. Pre-organogenesis stage occurred in first to fourth day after oviposition. Organogenesis stage can be observed in fifth to seventh day after oviposition. In the fifth day, body segmentation was completed. In the sixth day, cephal section and patterning of appendages was completed. Besides, the pigmentation of cephal also occurred in sixth day. In the seventh day, the pigmentation of entire body was completed and embryo was ready to hatch. In the eight day after oviposition embryo was hatching by cracking the eggshell.