In this study, we found that: (1) meta- morphosis time increased as larval density increased, and insufficient food supply prolonged the larval period; (2) from the low to high density the mean larval period was prolonged by ~2 d in the SF treatment and ~4 d in the IF treatment; and (3) from the SF to IF treatment the mean larval period was prolonged by ~20, ~22 and ~22 d at the low, medium and high densities, respectively (Table 1)