FLIGHT CAPACITY - GENETIC DETERMINATION AND PHYSIOLOGICAL CONSTRAINTSIN A MIGRATORY MOTH MYTHIMNA-SEPARATA

Flight capacity of the oriental armyworm Mythimna separata (Walker) (L epidoptera: Noctuidae) was estimated by a new tethered flight techniqu e. Samples of a migrant population showed a substantial proportion of 'long fliers'. Heritability of flight capacity was found to be signifi cant (h2 = 0.27). Female moths from a line selected for long pre-repro ductive period (PRP) showed greater flight capacity than those from a short PRP line. This difference was not apparent among males. Onset of calling behaviour inhibited the expression of flight capacity in fema les showing a clear 'oogenesis-flight syndrome'. These results are dis cussed in relation to seasonal migration in eastern China and the mech anisms involved in the migratory strategy of this species.