The Lepidoptera are one of the largest insect orders, including some 10 000 described Australian species, with at least as many again still to be named. They range in size from tiny leaf-miners, with wings expanding barely 3 mm, to the huge hepalids, cossids and saturniids expanding some 25 cm. Their colouring and elegance have given them considerable popular appeal, while the destructive qualities of the larvae of many species establish the economic importance of the order.
Members of this order are readily distinguished from other panorpoid orders having two pairs of wings by the clothing of usually broad, overlapping scales on the head, body and appendages of the adult. The wing venation of the primitive homoneurous suborders approaches that of certain Trichoptera, but M
rarely occurs as a separate vein terminating on the wing margin. An epiphysis is present on the fore tibia of most of these archaic Lepidoptera, as in all but a few of the more specialised families of the order, whereas this structure does not occur in other orders. The modification of the galeae into a proboscis (or haustellum), found widely in the Lepidoptera, occurs in no other order. Twenty-seven possible lepidopteran autapomorphies are listed by Kristensen (1984e).
The Australian Moths Online webpage, which is linked to the moth families of the Lepidoptera, was developed by Len Willan and CSIRO Entomology, and provided by Dr Marianne Horak, CSIRO Entomology.
Proboscis-bearing or rarely mandibulate, endopterygote Neoptera, without median ocellus, with two pairs of membranous wings clothed on both surfaces with usually overlapping scales. Larvae eruciform, peripneustic, or rarely holopneustic. Pupae rarely decticous, usually adecticous and obtect.
The major families of Lepidoptera are all represented in Australia, but the relative abundance of several groups differs markedly from that of other continents. Some sections apparently represent a Gondwanan fauna, while others are of Oriental origin, upon which has probably been superimposed further Oriental and Papuan elements in several waves.
Archaic families, such as the Hepialidae, Heliozelidae, Incurvariidae, Palaephatidae, Cossidae and Castniidae, are relatively richly represented, but whether this radiation took place in the absence of more advanced groups in the continent, or in competition with those groups in response to increasing aridity, is not clear. The larvae of these families are either leaf-miners or are adapted to feed within stems and roots or deep in the soil externally on roots; such behaviour patterns would greatly favour their survival in an arid environment. Concealed feeding and an outstanding adaptation to a dominant flora of
have probably also contributed to the abundance of species in the Oecophoridae which comprise more than a quarter of the fauna; oecophorids are especially abundant in the
forests and woodlands in both coastal and inland areas.
Groups which probably have reached Australia more recently, and which are still most abundant in the north, include the Sesiidae, Lecithoceridae, Papilionidae, Pieridae, Uraniidae, Sphingidae, Lymantriidae and Aganaidae, together with large sections of the Gelechiidae, Pyralidae, Geometridae, Notodontidae, Arctiidae and Noctuidae. Nevertheless, some of these families contain large blocks of endemic genera, notably the Oenochrominae (Geometridae). The Lophocoronidae, Anomosetidae, Cyclotornidae and Carthaeidae are confined to Australia and Anthelidae to Australia and New Guinea.