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The Mythimna (=Leucania) loreyi (Duponchel) has recently emerged as a major pest of grain crops in China, Little is known about its basic biology and ecology, making it difficult to predict its population dynamics. An age-stage, two-sex life table was constructed for this insect when reared on maize in the laboratory at five constant temperatures (18, 21, 24, 27, and 30 °C). Both the intrinsic rate of increase (r) and finite rate increase (A) increased as temperature significantly increased and mean generation time (7} decreased significantly with increasing temperature. The highest values for net reproductive rate (R0) and fecundity were observed at 24°C. However, M. loreyi was able to develop, survive, and lay eggs at all temperatures tested (18-30 °C). Development rates at different temperatures for the egg, larval, pupal, as well as for a total preoviposition period, fit a linear equation. The lower threshold temperatures of egg, larval, pupal, preoviposition, and total preoviposition period were 8.83, 10.95, 11.67, 9.30, and 9.65 °C, respectively. And their effective accumulated temperatures were 87.64, 298.51, 208,33, 66.47, and 729.93 degree-days, respectively. This study provides insight into the tempe rature-based phenology and population ecology in M. loreyi. The results will benefit population dynamics monitoring, prediction, and management of this insect pest in the field. [ABSTRACT FROM AUTHOR]