The Noctuid moths are the largest family of the order Lepidoptera, comprising more than 35.000 described species. They are distributed in all continents (except Antarctica) and inhabit a multitude of different habitats from arctic tundra to tropical rain forest and from high mountains to arid and semi-arid areas.
Their ecology is very diverse. Noctuid larvae feed mainly on grasses, herbaceous plants, shrubs, bushes, deciduous and evergreen trees, but also on lichens, mosses, algae, fungi, dry and rotting plant parts, on organic matter (detritus), and some are predacious on scale insects (Coccids). In a number of genera the larvae are internal feeders in stalks or roots and often pupate inside the plant. Otherwise Noctuids pupate between leaves and other plant parts, between or under bark, at or in the soil, in a simple chamber in the earth or in a weak to strong cocoon.
The perfect insects are generally good flyers, but a number of species in high mountains and on islands are subject to wing reduction. Most adults are crepuscular and nocturnal, some fly by day and by night and relatively few are entirely diurnal. They usually possess a well-developed proboscis with which they feed on floral nectar, aphid excretions, tree-sap, grass-flowers infested by Claviceps fungi, and fruit. The latter food is used especially in the tropics by species with a strong proboscis (fruit-piercing moths). One of these species has even developed a blood-sucking habit, attacking mammals and - in the laboratory - even man.
The identification of Noctuids using only external characters (i.e. wing markings and colour, wing shape, body vestiture, antennae, legs etc.) is difficult for two reasons. On the one hand some species show a tremendous individual variation, and on the other hand many species are very similar to each other - sometimes indistinguishable. Thus it is necessary to differentiate between characters (or character states) which are variable and therefore irrelevant for identification purposes and characters (or character states) which are diagnostically important.
Unfortunately there is no visible external character that defines the family Noctuidae and allows an easy separation from other families. Many of the "typical" Noctuids of the subfamilies Noctuinae, Hadeninae, Cuculliinae etc. can fairly easily be recognized externally by a combination of elements of wing-marking, wing shape and stature, but there are numerous species, especially in the other subfamilies, which closely resemble members of other families, most notably the Loopers (Geometridae), the Pyralids (Pyralidae), the Prominents (Notodontidae), the Thyatirines (Drepanidae: Thyatirinae), the Tortricids (Tortricidae), some Tiger Moths (Arctiidae) and others.
The beginner has no other choice than to become acquainted with the individual species (or to investigate structural characters like the thoracic tympanal organ, which is characteristic for the families of the superfamily Noctuoidea). A useful rule-of-thumb is the presence of an orbicular stigma, however, this can be reduced or missing in many of the poorly marked Noctuids, while it is occasionally present in other families (Notodontidae, Drepanidae).
As a matter of fact, there is still no definition of the family Noctuidae by anatomical characters; the division into subfamilies and the investigation of their phylogenetic relationships is still in full progress (Kitching & Rawlins 1999).
The best method of identification is always the comparison with an extensive collection so that the specimens can be compared directly and under identical conditions (light, background). Since large collections are available only in some museums, universities and a few private collections, most users have to take resort to the second best method: the comparison with specimens figured in books.
The print media, however, have their limitations. The quality of the original drawing, watercolour, or photograph may vary. As a look into any older work on Noctuids shows, the correct reproduction of wing shapes and of the very subtle markings is usually the critical factor which often defeats even notable illustrators. (It is not by accident that the truly great artists of Noctuid painting - like Jules Culot (1861-1933) - can be counted on the fingers of one hand.)
Only photography provides a means of faithful reproduction. When transferring photographs into print the limiting factor is screen size. Reproductions of small objects like insects in natural size - even with a fine screen - often fail to show important details so that additional figures in stronger magnification would be necessary. In most books space and cost limitations prevent the lavish use of illustrations. For the same reasons many books show only one specimen per species which is insufficient in a family like the variable Noctuids.
The medium CD permits to meet both demands: a large number of pictures which can be viewed up to a magnification as is necessary for identification purposes.
