ranges between 34–50 mm. Adult wingspan and body size are correlated with the nutritive status of the developing moth. Curved dorsal spurs located on the tibia of the forelegs distinguish this species from others very similar to it. Adult behavior Adults emerge from the end of April through the beginning of June. Shortly after emerging, the adult moths mate, as discussed in more detail in the mating section. The moth is most active at night, when it flies between plants and feeds. During the day, the adult moth seeks cover under the foliage of surrounding plants. Mating Mating in M. brassicae occurs among recently emerged adult moths. In one controlled observation, adults began mating the first night of emergence. In this observation, mating behavior started at ten in the evening, with most mating activity occurring after midnight. Mating pairs remained associated for upwards of twelve hours, with females covering male wings with the posterior of their body during this time. The pattern of mating is as follows: Calling position The females initiated the mating sequence. She does so by calling for the male which entails positioning her antennae forward, raising her wings horizontally, and flapping her wings quickly. If there is no male response to this call, the female relocates and repeats the calling behavior until she is able to successfully attract a male mate. Reaction of the male Upon hearing the call of the female, the male similarly points his antennae forward and begins to flap his wings rapidly. Then, the male takes off in flight to search for the calling female. Approach of male When the male locates the calling female, he approaches her and touches his antennae to her body as the first point of contact. This allows the male to confirm the identity of the calling female as belonging to the same species as itself. The male then moves towards the female and begins to flap its wings aggressively again. It then positions its abdomen towards the female's and opens his claspers to begin copulation. Copulation The female continues the calling as the male copulates with the female. The male must position his abdomen under the wing of the female during copulation. After copulation, the female will continue to mate. On average, a female will copulate 2.5 times. Oviposition The female moth lays eggs singly, but clusters many of them onto the same surface. A female