Dialectica imperialella is a moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 of the Gracillariidae

Gracillariidae

Gracillariidae is an important family of insects in the order Lepidoptera and the principal family of leaf miners that includes several economic, horticultural or recently invasive pest species such as the horse-chestnut leaf miner, Cameraria ohridella....

 family. It is found from Denmark

Denmark

Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...

 to the Pyrenees

Pyrenees

The Pyrenees is a range of mountains in southwest Europe that forms a natural border between France and Spain...

, Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 and Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 and from Great Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 to Russia

Russia

Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 and Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

.
Adults are on wing in May and June in one generation.

The larva

Larva

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e feed on Buglossoides purpurocaerulea, Lithospermum officinale

Lithospermum officinale

Lithospermum officinale or Common Gromwell or European Stoneseed is a plant species of the genus Lithospermum.Its leaves are eaten by the caterpillars of the moth Ethmia pusiella....

, Pulmonaria angustifolia, Pulmonaria officinalis

Pulmonaria officinalis

Pulmonaria officinalis, common name Lungwort or Common Lungwort, is an herbaceous evergreen perennial rhizomatous plant of the genus Pulmonaria, belonging to the family Boraginaceae-Etymology:...

and Symphytum officinale

Symphytum officinale

Symphytum officinale is a perennial flowering plant of the genus Symphytum in the family Boraginaceae. Along with several other species of Symphytum, it is commonly known as comfrey. To differentiate it from other comfreys, this species may be known as common comfrey, Quaker comfrey, and cultivated...

. They mine

Leaf miner

Leaf miner is a term used to describe the larvae of many different species of insect which live in and eat the leaf tissue of plants. The vast majority of leaf-mining insects are moths , sawflies and flies , though some beetles and wasps also exhibit this behavior.Like Woodboring beetles, leaf...

 the leaves of their host plant. The mine consists of a small, lower-surface spiralling corridor that soon becomes a blotch that overruns the previous corridor. Gradually, the mine becomes deeper, and finally is full depth locally. At the underside the mine is quite larger and membranous. The frass

Frass

Frass is the fine powdery material phytophagous insects pass as waste after digesting plant parts. It causes plants to excrete chitinase due to high chitin levels, it is a natural bloom stimulant, and has high nutrient levels. Frass is known to have abundant amoeba, beneficial bacteria, and fungi...

is initially deposited in strings, but later it becomes a network of thin threads. Pupation usually takes place outside of the mine.