Impact of temperature and relative humidity on life history parameters of adult \u3ci\u3eSitotroga cerealella\u3c/i\u3e (Lepidoptera: Gelechiidae)

The Angoumois grain moth, Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae), is a pest of stored corn, Zea mays L., and other grains throughout the world. Sitotroga cerealella are routinely exposed to temperatures below 20°C in regions of the U.S. where corn is grown, yet there are no data describing adult life history parameters below 20°C. We determined longevity, fecundity, and survivorship of eggs at a range of temperatures that represent environmental conditions to which S. cerealella are exposed in corn stored in the U.S. Longest male longevity was 31 d at 10°C, and shortest male longevity was 4 d at 35 and 40°C. Longest female longevity was 29 d at 15°C, and shortest female longevity was 5 days at 35 and 40°C. Duration of the preoviposition period was as long as 16 d at 10°C and as short as 1 d at 30-40°C. All females laid eggs at 20-30°C, 50-94% of females laid eggs at 15°C, and 17-61% of females laid eggs at 10, 35, or 40°C. Females laid the most eggs, nearly 100, at 20 and 25°C and 75% r.h., while 6 or fewer eggs were laid at 10, 35, or 40°C. Between 68 and 98% of eggs hatched at 20-30°C, while 20% or fewer eggs hatched at 35°C and no eggs hatched at 40°C. An average of less than one egg was laid at 10°C, but 58-100% of eggs hatched at 10°C. Our results emphasize the importance of including data on population growth of stored-grain insect pests at low temperatures in computer models for simulating insect population growth in grain