Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Taraxacum

1a > Leaf-miner: Mine associated with mid-rib.

2

1b > Leaf-miner: Mine not associated with mid-rib.

3

2a > Leaf-miner: Larva feeding in the mid-rib or flower stalk where a gall-like swelling is produced (see also Redfern et al., 2002: 453, fig. 914). Pupation at base of leaf, near exit hole prepared by larva prior to pupation (see also Redfern et al., 2002: 453, figs 915).

The larva lives in a corridor of just a few cm long within the midrib. The leaf is stunted and the midrib is strongy swollen, gall-like. In the end the mine turns red. Pupation within the mine, near a previously made exit in the upper surface of the mine.

On Taraxacum in Britain and elsewhere. Widespread, at least in south, in Britain.Widespread in continental Europe from Swiss Alps to Faroe Is. Also recorded from the East Palaearctic and Nearctic Region.

Phytomyza wahlgreni Rydén, 1944 [Diptera: Agromyzidae].

2b > Leaf-miner: A distinctive mine primarily above mid-rib, with irregular short lateral offshoots into leaf blade. Pupation external (Spencer, 1972: 51 (fig. 172), 55; Spencer, 1976: 270, 271 (fig. 486)).

Branched, whitish, upper-surface corridor; main axis overlying the midrib; side branches overlying the main lateral veins. (In Campanula and Phyteuma the mine is much less branched, sometimes nothing more than a corridor on top of the midrib). Frass in rather long strings. Usually the mines begins as a long and narrow, shallow, tortuous lower-surface corridor that ends upon the midrib but otherwise is not associated with the leaf venation. Often this initial corridor is filled with callus, and then even less conspicuous. Pupation outside the mine.

A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings.

Polyphagous. On more than 40 host genera in 15 families in Britain including Taraxacum. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae].

2c > Leaf-miner: Larva mines from the midrib. Pupation in the base of the hollow midrib.

Hosts in Britain unknown. On Taraxacum elsewhere. Added to the British checklist by Gibbs (2006a). Widespread in continental Europe

Ophiomyia nasuta Melander, 1913 [Diptera: Agromyzidae].

2d > Leaf-miner: A white mine along mid-rib, with offshoots into leaf blade. Pupation internal at base of mid-rib.

In Asteraceae the larva mostly lives as a borer in the midrib of the leaves. From there short corridors are made into the blade. Also a corridor can be made overlying the midrib. In Euphorbia a small mine is made in the bracts of the inflorescence. The final mine strongly resembles the one of Liriomyza strigata, but the branches are vritually free from frass; this is acccumulated in the resting place of the larva, in the base of the midrib. There also pupation takes place.

Forms a mine along the midrib and has feeding spurs into the leaf. Pupation is in the mine at the base of the midrib.

On Cicerbita, Leontodon, Sonchus and Taraxacum in Britain and numerous other genera of Asteraceae elsewhere. Widespread in south, but not common, in Britain. Widespread in continental Europe.

Ophiomyia beckeri (Hendel, 1923) [Diptera: Agromyzidae].

The mine begins as a very narrow, upper- or lower-surface corridor, somewhere in the blade. When this hits a thick vein the larva uses this to descend towards the midrib. From that moment the lave lives in the hollow midrib. From here short, lobate corridors enter the leaf blade. The larva may move to another leaf by way of the leaf base. The corridors in the leaf are virtually free of frass (at most a few grains where they leave the midrib); frass is concentrated in the base of the midrib. Here also the pupation takes place.

On Crepis, Hypochaeris, Lapsana, Mycelis, Picris, Sonchus, Taraxacum and possibly Bellis in Britain and additional genera of Asteraceae elsewhere. Widespread in Britain and throughout much of Europe.

Ophiomyia cunctata (Hendel, 1920) [Diptera: Agromyzidae].

2f > Leaf-miner: A whitish blotch-mine along the mid-rib, with lateral offshoots into the leaf blade. Pupation at base of leaf in petiole (Spencer, 1972b: 25).

Broad corridor overlying the midrib, with short excursion into the blade, mainly in its basal part. Frass concentrated in the basal part of the mine, corridors almost free from frass. Pupation in the mine, also in the basal part.

On Crepis, Hieracium, Hypochaeris, Leontodon, Picris, Pilosella, Sonchus and Taraxacum in Britain and additional genera of Asteraceae elsewhere. Widespread and common in Britain and continental Europe. Range extending east to Siberia. Also recorded from Canada.

Ophiomyia pulicaria (Meigen, 1830) [Diptera: Agromyzidae].

3a > Leaf-miner: A narrow, whitish linear mine. Pupation internal (Spencer, 1976: 416).

Upper-surface, less often lower-surface corridor. Frass in isolated grains. Puparium within the mine, usually at the lower surface.

On Leontodon autumnalis and Taraxacum officinale in Britain and elsewhere. Britain and the Republic of Ireland. Widespread in continental Europe.

Chromatomyia farfarella (Hendel, 1935) [Diptera: Agromyzidae].

3b > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal, at the end of the mine with the anterior spiracles projecting through the epidermis (Spencer, 1976: 433).

Upper-surface, less often lower-surface corridor. Frass in isolated grains. Pupation within the mine, usually in a lower-surface puparial chamber.

A long whitish upper surface corridor, which eventually goes lower surface.

Two highly polyphagous species of Chromatomyia, with indistinguishable mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau) which can only be distinguished by the male genitalia. Both species are widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae. Records on Asteraceae not based on examination of male genitalia are treated in this account as Chromatomyia 'atricornis'.

Chromatomyia horticola is recorded on 160 plant genera in 31 families, of which 55 plant genera in 19 families, but not yet on Taraxacum, in Britain. On Taraxacum elsewhere.

Chromatomya syngenesiae is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, including Taraxacum in Britain.

Chromatomyia 'atricornis' has been recorded on Taraxacum in Britain.

Chromatomyia horticola (Goureau, 1851) [Diptera: Agromyzidae]
OR
Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

3c > Leaf-miner: Larva mining both lower and upper surface, unusually long, linear, conspicuously broad, frequently largely on the underside of the leaf. Pupation external (Spencer, 1972b: 76 (fig. 251); Spencer, 1976: 445 (fig. 780), 446).

Corridor mine. The first part consists of a very long and narrow lower-surface corridor; the mine is quite shollow here, and often inconspicuous. The second part is upper-surface, uusally much shorter, and widens abruptly. Pupation outside the mine.

On Crepis, Hieracium, Lapsana, Picris, Pilosella, Senecio, Sonchus and Taraxacum in Britain and additionally other genera of Asteraceae elsewhere. Widespread in southern Britain, also Sutherland, Inner Hebrides and Warwick. Also recorded in the Republic of Ireland and Widespread in much of Europe.

Phytomyza marginella Fallén, 1823 [Diptera: Agromyzidae].

3d > Leaf-miner: A long, winding leaf-mine on the upper surface of the leaf, with frass widely-spaced in conspicuous black lumps. Pupation internal, at the end of mine (Spencer, 1972b: 28 (fig. 68), 29).

On Solidago, but not yet on Taraxacum, in Britain. On Aster, Callistephus, Erigeron, Sonchus, Solidago and Taraxacum elsewhere. Only recorded from Kent, Derby, Warwick and East Kent in Britain. Widespread in much of Europe. Also recorded in Japan, Canada and the U.S.A.

Ophiomyia maura (Meigen, 1838) [Diptera: Agromyzidae].

3e > Leaf-miner: Egg is laid beneath the epidermis on the upper leaf surface. Larva mines in basal leaves. Pupation internal (Spencer, 1976: 74).

Little branched corridors, radiating from the leaf base, often deep in the plant tissue. The larva can migrate from one leaf to the other through the petioles. Frass concentrated in the lowest, basal part of the mine; there also the pupation takes place.

On Cichorium and Leontodon, but not yet on Taraxacum, in Britain and in addition Lactuca and Taraxacum elsewhere. Uncommon, but widespread in Britain. Widespread in continental Europe, range extending eastwards to Tadzhik S.S.R and Uzbek S.S.R.

Ophiomyia pinguis (Fallén, 1820) [Diptera: Agromyzidae].

3f > Leaf-miner: The mine begins with a very narrow full depth corridor, that ends upon the midrib. Subsequently a broad corridor, or rather an elongated blotch, is made overlying the midrib; from here broad, lobe-like extensions are made into the blade. Frass in discrete grains. Secondary feeding lines conspicuous. The larva is capable of leaving the mine and restarting in a new leaf, in which case the association with the midrib may be lost. Pupation after vacation of the mine.

On Cichorium, Crepis, Hieracium and Taraxacum in Britain and additionally other genera of Asteraceae elsewhere. North-east Scotland, also throughout Ireland and continental Europe, except the Mediterranean area.

Trypeta immaculata (Macquart, 1835) [Diptera: Tephritidae].

3g > Leaf-miner: A small somewhat irregular, elongate blotch (Spencer, 1972b: 57; Spencer, 1976: 273 (fig. 491), 274).

Elongated upper-surfcace blotch with fairly little frass in loose grains. Pupation outside the mine; exit slit in upper epidermis.

On Leontodon and Taraxacum in Britain and Aposeris, Arnoseris, Leontodon and Taraxacum elsewhere, Widespread in Britain and continental Europe.

Liriomyza taraxaci Hering, 1927 [Diptera: Agromyzidae].

3h > Leaf-miner: The mine begins in the midrib, especially in a lower leaf, extending into the leaf disc, branching irregularly or pinnately, may also locally be blotch like. The mine is brown and very transparent. Sides very irregularly eaten out. Frass loosely dispersed or in a loose central line, buy may also be pressed against the sides of the corridor. The larva may also leave the mine and restart elsewhere.

Polyphagous. On numerous genera and species in several plant families, including Taraxacum, in Britain and elsewhere. Widespread in England and continental Europe. Also recorded in the Republic of Ireland.

Orthochaetes setiger (Beck, 1817) [Coleoptera: Curculionidae].