PHYSIOLOGICAL ECOLOGY Development and Survivorship of Immature Angoumois Grain Moth (Lepidoptera: Gelechiidae) on Stored Corn

Life history of immature Angoumois grain moths, Sitotroga cerealella (Olivier), was studied on dent corn (Pioneer 3320) at 10, 15, 20, 25, 30, 35, and 40 C and at 43, 53Ð61, 75Ð76, and 82Ð87% RH under laboratory conditions. At 10 and 40 C, none of the stages survived at any relative humidity. Temperaturewas themain factor affecting egg incubationperiod, larval-pupal development time, and egg and larval-pupal survivorship. The shortest egg development times occurred at temperatures of 30 C and higher, but they increased sharply as temperature decreased. Larval-pupal development timewas shortest at 30 C.Survivorshipwasoptimal at 20Ð30 Cforeggs and larvae-pupae, but larval-pupal survivorship decreased sharply at 15 and 35 C. Duration of larval-pupal development did not vary with sex. Newly emerged females were twofold heavier thanmales, and temperature and relative humidity did not affect weight. Sex ratio of emerging adults did not differ from 1:1 at any temperature or relative humidity. The optimumconditions for development of Angoumois grainmoth on corn were 30 C and 75% RH. The data will be useful for determining safe storage conditions for corn and for developing a computer model for simulating population dynamics of immature S. cerealella.