As in other animals, diet is known to influence insect reproduction, and its impact has been intensively investigated in females. In our study, we examined the effects of various diets on male reproductive success in the moth Agrotis ipsilon, a pest of many crops. Our experiments showed an increase in the rates of fertilization and hatching when males fed with various sugars (sucrose, fructose, and glucose) supplemented with sodium. Such results provide valuable initial information on the nutritional ecology of male moths and could serve to the development of nutritional attractants for the management of crop pests.