The effect of starvation on selected silkworm genetic resources was studied on economic and biochemical parameters and nutritional indices to identify the genetic hardiness. Approximate digestibility (AD), Consumption index (CI), Reference ratio (RR), Efficiency of conversion of ingesta and of digesta (ECI and ECD) to larval body, cocoon, shell, ingesta and digesta per gram (I/g and D/g) cocoon and shell were used to measure genetic hardiness. A significant improvement on growth and enzyme activity /stability was observed in promising silkworm breed BBE-0164 and BBI-0341 as a result of reduced feeding amount offered the role of feeding restriction on growth and enhanced biochemical activity is discussed. Also these races showed the presence of thermo stable esterase enzyme resisting temperature upto 60̊ C. These parameters may throw a better light on how best these races /breeds could be effectively reared under minimal food availability and utilized for breeding as a better stress tolerant pure breeds.