Abstract
1. In order to evoke the uniform and prompt feeding response of the newly hatched larvae of the silkworm against the artificial feed, it was highly desirable to include mulberry leaf powder or mulberry leaf extracts as feeding-stimulating substances.
2. The newly hatched larvae showed a week feeding response against the artificial feed B (Tabel 1) which does not contain any feeding-stimulating substances, and no larva started an active feeding for the first 24 hours (Table 3). Newly ecdysed, unfed 2nd-instar larvae, however, showed some feeding response, and the number of larvae showing an active feeding behavior increased with the progression of larval instar, eventually 97% in the 5th instar. Thus, it is suggested that the range of feeding response of the silkworm is narrow in the younger larvae, but becomes wider gradually according to the growth of the larva.
3. Applying the results as mentioned above (1 and 2), the rearing of the silkworm throughout on the artificial feed was successfully achieved, where the dietary level of the mulberry leaf powder was decreased gradually, 10% in the feed for the 1st-instar larvae and finally no addition in the feed for the 5th-instar larvae (Table 5).
4. A brief discussion was made on the gradual changes in feeding response of the silkworm with instar progression and also advantageous points of the present rearing method reducing the dietary mulberry leaf powder with larval age.
