Pattern of energy allocation for reproduction was studied as a function of feeding regimes in the silkwormBombyx mori. The larvae were restricted to feed for 6, 12, 18 or 24 h (ad libitum). Restriction of feeding duration resulted in slow growth and extended larval duration. Consumption, assimilation, conversion and metabolism and their rates showed steady increase with the increase in the feeding duration. On pupation, energy allocation for egg production was studied by dissecting the pupa and estimating the reproductive and body tissues separately during the entire pupal period. Length and biomass of ovary steadily increased with increasing feeding duration as well as with increasing age of pupa. During egg development, the tissue protein was transferred to the ovary. This type of conversion was more in those fedad libitum than in those restricted to feed for shorter durations. Tissue fat and ovarian fat decreased as a function of age of pupa, indicating that fat served as the main source of energy for pupal metabolism.Bombyx mori restricted to feed for 6 h duration allocated 55% pupal energy for reproduction while those fedad libitum allocated about 67% of the pupal energy for reproduction. However, they allocated about 15–19% of assimilated energy for egg production in all the feeding regimes.