s spans 130–95 mya from their earliest forms to domination of vegetation. Lepidoptera and
Trichoptera (caddisflies) are more closely related to one another than to any other taxa, sharing many similarities that are lacking in other insect orders; for example the females of both orders are
heterogametic, meaning they have two different
sex chromosomes, whereas in most species the males are heterogametic and the females have two identical sex chromosomes. The adults in both orders display a particular wing venation pattern on their forewings. The larvae of both orders have mouth structures and a gland with which they make and manipulate
silk.
Willi Hennig grouped the two orders into the
Amphiesmenoptera superorder; they are sisters, and together are sister to the extinct order
Tarachoptera.
Micropterigidae,
Agathiphagidae and
Heterobathmiidae are the oldest and most
basal lineages of Lepidoptera. The adults of these families do not have the curled tongue or
proboscis, that are found in most members order, but instead have chewing
mandibles adapted for a special diet. Micropterigidae larvae feed on
leaves,
fungi, or
liverworts (much like the
Trichoptera). Adult Micropterigidae chew the pollen or spores of ferns. In the Agathiphagidae, larvae live inside
kauri pines and feed on seeds. In Heterobathmiidae the larvae feed on the leaves of
Nothofagus, the southern beech tree. These families also have mandibles in the pupal stage, which help the pupa emerge from the seed or cocoon after
metamorphosis. The
Eriocraniidae have a short coiled proboscis in the adult stage, and though they retain their pupal mandibles with which they escaped the cocoon, their mandibles are non-functional thereafter. Most of these non-ditrysian families, are primarily
leaf miners in the larval stage. In addition to the proboscis, there is a change in the scales among these basal lineages, with later lineages showing more complex perforated scales. With the evolution of the
Ditrysia in the mid-Cretaceous, there was a major reproductive change. The Ditrysia, which comprise 98% of the Lepidoptera, have two separate openings for reproduction in the females (as well as a third opening for excretion), one for mating, and one for laying eggs. The two are linked internally by a seminal duct. (In more basal lineages there is one
cloaca, or later, two openings and an external sperm canal.) Of the early lineages of Ditrysia,
Gracillarioidea and
Gelechioidea are mostly leaf miners, but more recent lineages feed externally. In the
Tineoidea, most species feed on plant and animal detritus and fungi, and build shelters in the larval stage. The
Yponomeutoidea is the first group to have significant numbers of species whose larvae feed on herbaceous plants, as opposed to woody plants. They evolved about the time that flowering plants underwent an expansive
adaptive radiation in the mid-
Cretaceous, and the Gelechioidea that evolved at this time also have great diversity. Whether the processes involved
co-evolution or sequential evolution, the diversity of the Lepidoptera and the angiosperms increased together. In the so-called "
macrolepidoptera", which constitutes about 60% of lepidopteran species, there was a general increase in size, better flying ability (via changes in wing shape and linkage of the forewings and hindwings), reduction in the adult mandibles, and a change in the arrangement of the crochets (hooks) on the larval prolegs, perhaps to improve the grip on the host plant. Many also have
tympanal organs, that allow them to hear. These organs evolved eight times, at least, because they occur on different body parts and have structural differences. The main lineages in the macrolepidoptera are the
Noctuoidea,
Bombycoidea,
Lasiocampidae,
Mimallonoidea,
Geometroidea and
Rhopalocera. Bombycoidea plus Lasiocampidae plus Mimallonoidea may be a
monophyletic group. The Rhopalocera, comprising the
Papilionoidea (butterflies),
Hesperioidea (skippers), and the
Hedyloidea (moth-butterflies), are the most recently evolved. There is quite a good fossil record for this group, with the oldest skipper dating from . ==Fossil Lepidoptera taxa==