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

  

OMPHALODES. Blue-eyed-Mary. [Boraginaceae]

Two species of Omphalodes are recorded in Britain. Both are introduced and include Blue-eyed-Mary (O. verna).

Three British miners, all Diptera, are recorded on Omphalodes.

A key to the European miners recorded on Omphalodes is provided in Bladmineerders van Europa.

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

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.

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, but not yet on Omphalodes, 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: A narrow linear leaf-mine, which developes into a large blotch. Several larvae frequently feed together and the resulting mine can entirely fill the leaf (Spencer, 1976: 89).

The mine begins with a narrow, parallel sided corridor af 1-8 cm in length, with a nice double frass line. After the first moult the corridor is succeeded, and mostly overrun, by a large, primary, brown blotch. Frass in the initial corridor in short thread fragments, in the blotch in angular granules and thread fragments that often are branching (the frass is unusally sticky). Primary and secondary feeding lines conspicuous. The final mine often is very large and generally contains several larvae, because normally several mines develop on a leaf, and coalesce into one big blotch. Before pupation the larvae leave the mine through a semicircular exit slit that mostly, but not invariably, is in the upper epidermis.

The initial narrow gallery contains frass in a double line. It then expands to form a blotch mine. Several larvae may occupy a leaf to form a large blotch.

On numerous genera of Boraginaceae, including Anchusa, Borago, Cynoglossum, Echium and Pulmonaria, but not yet on Omphalodes, in Britain. Widespread in Britain. Also recorded in the Republic of Ireland. Common and widespread throughout most of Europe.

Agromyza abiens Zetterstedt, 1848 [Diptera: Agromyzidae].

1c > Leaf-miner: Mine initially linear, later developing into a whitish blotch. Pupation in mine on lower surface (Spencer, 1972b: 90).

Rather small upper-surface secondary blotch in the leaf apex, generally beginning with a short corridor that mostly is overrun by the later blotch. No feeding lines recognisable. The final part of the mine is a lower-surface corridor, mostly following a vein and containing no frass. At its end an exit slit is made; mostly the larva pupariates within the mine, just before the exit.

On Mysotis, but not yet on Omphalodes, in Britain and on Myosotis and Omphalodes elsdewhere. Widspread in Britain an elsewhere.

Phytomyza myosotica Nowakowski, 1959 [Diptera: Agromyzidae].

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