Reproductive behavioural studies on the fall armyworm, Spodoptera frugiperda (J.E. Smith) were investigated at temperature 27 ± 2ᵒC and Relative humidity of 65–70% and photoperiod of 12L: 12D at Department of Agricultural Entomology UAS, Raichur. Adult emergence of moths was observed throughout the day. Wherein, 22.5 per cent of moths emerged during photophase (6.00pm to 5.00am) and 77.50 per cent of moths emerged during scotophase (18.00 to 12.00). Calling behaviour of S. frugiperda females observed from one to eight days. Female started calling from 2nd hour of scotophase (19.00) and terminated at 11th hour of scotophase (04.00). The mean number females called was maximum at 6th hour of scotophase in three-day old moth. None of the females called during 1st hour of scotophase. Mating of S. frugiperda observed throughout scotophase up to 8 days. The results showed that highest mating occurred in three day old moths. These studies provide valuable information for indentation of sex pheromones and also helps in semiochemical based pest management.