Spodoptera litura, otherwise known as the tobacco cutworm or cotton leafworm, is a nocturnal moth in the family Noctuidae. S. litura is a serious polyphagous pest in Asia, Oceania, and the Indian subcontinent that was first described by Johan Christian Fabricius in 1775. Its common names reference two of the most frequent host plants of the moth. In total, 87 species of host plants that are infested by S. litura are of economic importance. The species parasitize the plants through the larvae vigorous eating patterns, oftentimes leaving the leaves completely destroyed. The moth's effects are quite disastrous, destroying economically important agricultural crops and decreasing yield in some plants completely. Their potential impact on the many different cultivated crops, and subsequently the local agricultural economy, has led to serious efforts to control the pests. S. litura is often confused with its close relative, Spodoptera littoralis. These two species are hard to discriminate between because the larvae and adult forms are identical. Inspecting the genitalia is the most certain way to tell the two species apart. Description Sex differences Morphology There are slight but obvious differences in morphology between males and females of S. litura that allow for the easy differentiation of the two sexes. Male forewing length is while female forewing length is slightly larger and measures . The orbicular spot on the forewing is also more pronounced in the males. Differences in food regulation Regulation of macro nutrient input differs between males and females. Experimental results show that when S. litura are presented with two nutritionally complementary diet options, one rich in protein and a second rich in carbohydrates, females tend to consume more protein than males while no differences in carbohydrates exist. Body utilization of the macro nutrients differed as well. Females were very efficient at converting the protein consumed into body growth and mass, reflecting the bodily requirements to produce eggs. Males, on the other hand, were more efficient at depositing lipid from ingested carbohydrates. This fits in well with the migration patterns associated with mating. Males usually go out to find females during mating season, so the lipid deposits are thought to be energy reserves that will help the males in preparation for the migration. Similar species Spodoptera litura and Spodoptera littoralis are very closely related species. Discriminating between the two species can be difficult because the larvae and adult forms look identical. In fact, these two