The Noctuidae is the largest family of macro-moths in the British Isles, with just over 400 species. Worldwide, there are an estimated 21,000 valid specie’s described, and the family is well represented in every continent.
Most British noctuids are medium-sized, stout-bodied, frequently brown moths, with forewings often substantially longer than they are deep. Most are specialised for powerful, manoeuvrable flight and fly mainly at night. The majority of long-distance migrant moths are noctuids. They require regular re-fuelling for flight, and feed at flowers, oozing tree-sap and aphid honeydew or sugary baits. The exceptions in terms of body form are the snouts, fanfoots and allies, which sometimes occur as immigrants and are generally brown, but which have not become specialised for powerful flight and retain deep wings and slight bodies, more like geometrid moths. The Waved Black, for example, rests on vertical surfaces with itswings spread flat and is so like a geometrid moth in build that it is often mistaken for one.
However, most noctuid moths rest with the trailing edges of the forewings brought together or slightly overlapping, over the folded hindwings, and hold their wings tent-like over the body. In the Noctuinae, popularly known as darts, the narrowed forewings are held horizontally over the body in the same plane, and overlap to a much greater extent, making the insect much narrower and more able to slip between vertical stems and grass blades in the open grassy places in which they predominate.
There is usually a conspicuous kidney-shaped marking and an adjacent oval and other marks in the central area of the forewing of noctuid moths, and as the thyatirid moths are the only other group of macro-moths with these marking, the kidney mark and oval can be useful recognition features. The size, shape and colour of these marking are often helpful in distinguishing particular species from close relatives.
The majority of noctuid moths have bald larvae (a notable exception being the daggers). The full complement of five pairs of claspers (prolegs) is usually present, but in the Hermioniinae (fan-foots), Catocalinae (red underwings), Hypeninae (snouts) and Plusiinae (Ys and brasses) they are often reduced to three or four pairs, including the anal claspers. Most noctuid larvae feed on the leaves, stems or roots of grasses or broadleaved herbaceous plants, but some feed on the foliage of trees and shrubs, most notably daggers, quakers, drabs, chestnuts, sallows, red underwings and fan-foots. Those dependent on grasses and herbs tend to overwinter as larvae, feeding in mild periods from autumn to spring. Those on tress and shrubs tend to overwinter as eggs or pupae. The larval period of some coincides with the flowers, fruits or tender spring leaves, but others can cope with the older leaves or seek out new late summer growth. Most noctuid have one generation per year in the British Isles.
While the majority pupate on or below ground, or sometimes in surface leaf litter, some, particularly those feeding in trees and shrubs, pupate in cocoons attached to leaves, tree trunks, fences and other objects, so that the whole life cycle may take place in the tree canopy.
(Taken from Waring and Townsend’s Field Guide to the Moths of Great Britain and Ireland)