Microlepidoptera
Microlepidoptera (micromoths) is an artificial (i.e., unranked and not monophyletic) grouping of moth families, commonly known as the "smaller moths" (micro, Lepidoptera).
These generally have wingspans of under 20 mm, so are harder to identify by external phenotypic markings than macrolepidoptera.
They present some lifestyles that the larger Lepidoptera do not have, but this is not an identifying mark.
Some hobbyists further divide this group into separate groups, such as leaf miners or rollers, stem or root borers, and then usually follow the more rigorous scientific taxonomy of lepidopterans.
Vernacular usage divides the Lepidoptera simply into smaller and larger or into more-primitive and less-primitive groups, microlepidoptera and macrolepidoptera, respectively.
This paraphyletic assemblage, however, includes also the superfamilies Zygaenoidea, Sesioidea, and Cossoidea that would in common parlance normally be lumped with the "macros".
For example, the Hepialidae or "swift moths" (up to 25 cm wingspan) fall quite basally in the lepidopteran "tree of life".
The recently discovered primitive superfamily Andesianoidea is another case in point; lurking within the Cossoidae until 2001, these moths have up to an order of magnitude greater wingspan (5.5 cm) than most previously known monotrysian "micros".
Whilst the smaller moths are usually also more seldom noticed, a more expansive "nonmacrolepidopteran" concept of the microlepidoptera would include about 37 out of the roughly 47 superfamilies.
Whilst usually less popular, micros are thus more important in the sense that they include a much wider span of the "tree of life" (i.e., phylogenetic diversity).
Whereas they include no butterflies, micros do also include a surprising number of day-flying groups, and the advent of online identification resources in many countries (e.g. "UK moths"[1]) combined with the widespread use of digital macrophotography, is making them much easier to identify.
Microlepidoptera can be found in a broad variety of habitats and ecological niches worldwide, both terrestrial and freshwater aquatic (e.g. Acentropinae).
They have a wide variety of feeding habits in both larval and adult life stages.
Caterpillars feed on a wide variety of plant tissue and across a wide spectrum of plant groups from liverworts to angiosperms.
They are either external feeders ("exophagous") or more usually feed internally ("endophagous"), typically as miners or tunnellers, but some feed on fungi, scavenge on dead animals, are parasitoids usually of other insects (some Zygaenoidea) or are detritivores, and Hyposmocoma molluscivora even feeds on live snails.
Adult moths feed with mandibles on spores and pollen (Micropterigidae) on dew (e.g. Eriocraniidae), with their probosces on nectar (many groups e.g. Choreutidae) or are simply nonfeeding with mouthparts reduced or absent.
The larvae of many smaller moths are considered economic pests, causing damage to plants, as well as fabrics and other manmade goods.
The first four superfamilies listed here may comprise 90% of species in a sample of smaller moths and the listed characters may be of some assistance to sort these out, particularly the form of the labial palp and scaling of the proboscis (Robinson et al. 2001).
'Archaic and primitive macros' is not a recommended name for these as it may create confusion of their placement in some classification systems.
