Impact of temperature and relative humidity on life history parameters of adult Sitotroga cerealella (Lepidoptera: Gelechiidae)

• We determined reproductive parameters of Sitotroga cerealella from 10 to 40 °C.
• Sitotroga cerealella laid viable eggs from 10 to 35 °C.
• We quantified longevity, fecundity, preoviposition period, and oviposition period.
• Simulation models for this pest should include life history at low temperatures.

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.