They are characterized by a structure in the metathorax called the nodular sclerite or epaulette, which separates the tympanum and the conjunctiva in the tympanal organ.
The names "armyworms" and "cutworms" are based on the behavior of the larvae of this group, which can occur in destructive swarms and cut the stems of plants.
Some species, such as the setaceous Hebrew character (Xestia c-nigrum), can be found in the Arctic Circle, specifically in the Yukon territory of western Canada, with an elevation 1,702 m above sea level, where the temperature fluctuates between 23/-25 °C (73/-13 °F).
[20] Moreover, many noctuid larvae, such as those of the fall armyworm (Spodoptera frugiperda) and of genera such as Heliothis and Helicoverpa, aggressively eat their siblings and often other species of caterpillar.
[22] As is common in members of the order Lepidoptera, courtship in many Noctuidae includes a set of movements in which the female evaluates the male's reproductive fitness.
First, the pyrrolizidine alkaloid sequestration usually present in Arctiinae is also found in a few species of noctuids, including the Spanish moth (Xanthopastis timais).
[27] Finally, the last type of chemical defense is regurgitation of plant compounds, often used by many insects, but the cabbage palm caterpillar (Litoprosopus futilis) produces a toxin called toluquinone that deters predators.
[25] Finally, all adults have another mechanism for defense: a tympanal organ available to hear the echolocation spread out by bats, so the moths can avoid them.
Their larvae are typically known as "cutworms" or "armyworms" due to enormous swarms that destroy crops, orchards and gardens every year.
[31] In West Africa, species including Busseola fusca, Heliocheilus albipunctella, Sesamia calamistis, Helicoverpa armigera, and Spodoptera exempta are major pests of staple crops such as pearl millet, sorghum, and maize.
[32] Since molecular analysis began to play a larger role in systematics, the structure of many Lepidoptera groups has been changing and Noctuidae is not an exception.
Most recent studies have shown that Noctuidae sensu stricto is a monophyletic group, mainly based on trifine venation.