Abstract  [Objectives]  To study the flight capacity, energy content and fecundity of the beet webworm (Loxostege sticticalis L.), at different temperatures. [Methods]  Three-day-old adults were tethered for 10h in a flight mill to test their flight capacity at different temperatures, after which their triglyceride, glycogen and protein content were measured using the corresponding assay kit, and their fecundity assessed. [Results]  18-22 ℃ was the optimal flight temperature. Triglyceride and glycogen content were significantly lower in flight-tested moths than in the control group and those flight-tested at 18-22 ℃ had the lowest triglyceride and glycogen content. There was no significant difference in protein content and fecundity between flight-tested moths and the control group. [Conclusion]  18 ℃ to 22 ℃ was the optimal flight temperature range for the beet webworm, and triglyceride and glycogen are the main energy source for flight. 10h of tethered flight did not affect the fecundity of 3-day-old moths.