Weights of \u3ci\u3ePolia Grandis\u3c/i\u3e Pupae Reared at Two Constant Temperatures (Lepidoptera: Noctuidae)

Sibling Polia grandis (Boisduval) larvae were reared at two constant temperatures on fresh foliage of quaking aspen (Populus tvemuloides Michx.). Female pupae developing at 25°C were 24% heavier than those developing at 30°C and corresponding males were 32% heavier. Duration of the larval period averaged 51 days at the former temperature and 41 days at the latter. Based on other Lepidoptera, a 24% change in pupal weight affects fecundity by 28 to 130 eggs per female. Fluctuations in larval temperature regime might induce size and fecundity variation in natural populations of grandis and other Lepidoptera