The leaf and stem mines of British flies and other insects
 

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds

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COREOPSIS. Large-flowered Tickseed [Asteraceae]


Four species of Coreopsis are recorded in Britain, all introduced. These include Large-flowered Tickseed (C. grandiflora), Garden Tickseed (C. tinctoria), Whorled Tickseed (C. verticillata) and C. nuecensis.

Three British miners are recorded on Coreopsis.

A key to the European miners recorded on Coreopsis is provided in Bladmineerders van Europa. This insludes Chromatomyia cf. syngenesiae, Liromyza strigata and Ophiomyia beckeri.



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


1a > 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 (Bladmineerders van Europa).

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

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

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

1b > Leaf miner: Mine not primarily above mid-rib.

2

2a > 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 (Bladmineerders van Europa).

A long whitish upper surface corridor, which eventually goes lower surface (British leafminers).

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'.

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

Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

2b > 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 (Bladmineerders van Europa).

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

On Cicerbita, Leontodon, Sonchus and Taraxacum, but not yet on Coreopsis, 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].



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