Starving fourth-instarAgrotis ipsilon(Hufnagel) for 4 d did not increase the propensity of 3-d-old moths to engage in long-duration (i.e., ≥1 h) continuous flights, or the duration of such flights, on flight mills. Adult diet (nothing, distilled water, or honey–water) did not significantly influence male flight propensity until 2 d of age or female propensity until 3 d of age. Male propensity to fly and flight profiles (flight duration, times of flight initiation and termination) seem to depend more upon the availability of liquids than carbohydrates, whereas female behavior is more dependent on a carbohydrate source. In all instances, the influence of both larval and adult diet stress on flight propensity and duration is negative. One would expect a positive effect if such stress factors act as cues that trigger a behavioral or physiological shift to a migratory phase. Instead, environmental factors that stress individuals seem only to decrease the already high propensity to make prolonged flights and decrease the duration of those flights.