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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CAMPANULA. Bellflowers and Harebells. [Campanulaceae]


Twenty species of Campanula are recorded in Britain. These include the native species Clustered Bellflower (C. glomerata), Giant Bellflower (C. latifolia), Spreading Bellflower (C. patula), Harebell (C. rotundifolia) and Nettle-leaved Bellflower (C. trachelium) and the introduced Canterbury-bells (C. medium), Cornish Bellflower (C. alliariifolia) and Creeping Bellflower (C. rapunculoides).

Seven British miners are recorded on Campanula.

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

Clustered Bellflower - Campanula glomerata. Image: © Brian Pitkin
Clustered Bellflower
Campanula glomerata



Key for the identification of the known mines of British
Diptera recorded on Campunula


Note: Diptera larvae may live in a corridor mine, a corridor-blotch mine, or a blotch mine, but never in a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Pupation never in a cocoon. All mining Diptera larvae are leg-less maggots without a head capsule (see examples). They never have thoracic or abdominal legs. They do not have chewing mouthparts, although they do have a characteristic cephalo-pharyngeal skeleton (see examples), usually visible internally through the body wall. The larvae lie on their sides within the mine and use their pick-like mouthparts to feed on plant tissue. In some corridor miners frass may lie in two rows on alternate sides of the mine. In order to vacate the mine the fully grown larva cuts an exit slit, which is usually semi-circular (see Liriomyza huidobrensis video). The pupa is formed within the hardened last larval skin or puparium and as a result sheaths enclosing head appendages, wings and legs are not visible externally (see examples).

See Key to non-Diptera.


1a > Stem miner: An external stem mine with frass in two rows of disconnected strips. Pupation in stem at end of mine (Spencer, 1972b: 25; Spencer, 1976: 61 (fig. 63B), 65-6).

Polyphagous. On Campanula, Jasione, Phyteuma [Campanulaceae], Crepis, Hypochaeris and Lapsana [Asteraceae] in Britain and additional genera of both families elsewhere. Uncommon in Britain - recorded in London, Warwick and Cambridge. Uncommon but Widespread in continental Europe.

Ophiomyia heringi Stary, 1930 [Diptera: Agromyzidae].

1b > Leaf-miner

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2a > 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 in Britain including Campanula. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

2b > Leaf-miner: Mine not primarily above mid-rib.

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3a > Leaf-miner: A shallow whitish linear-blotch mine (Spencer, 1976: 164-5, fig. 300).

Upper-surface blotch, preceded by a very short corridor. Often several larvae in a mine. Frass in isolated grains. Pupation outside the mine; exit slit in upper epidermis (Bladmineerders van Europa).

On Campanula glomerata and Campanula rotundifolia in Britain. In addition on other genera and species of Campanulaceae elsewhere. Recorded in England. Also recorded in the Republic of Ireland. Widespread in continental Europe. Also recorded in Japan.

Amauromyza gyrans (Fallén, 1823) [Diptera: Agromyzidae].

3b > Leaf-miner: An irregular whitish linear mine which can broaden at end and become blotch-like (Spencer, 1976: 397).

On Campanula glomerata, Campanula rotundifolia and Campanula trachelium in Britain. In addition on other species of Campanulaceae elsewhere.

Phytomyza campanulae Hendel, 1920 [Diptera: Agromyzidae].

3c > Leaf-miner: Very long, rather deep corridor, initially lower-surface, later upper-surface. In smaller leaves almost always a secondary blotch originates, that can occupy the entire leaf. Frass initially in pearl strings, later in scattered aggregations. Pupation outside the mine; exit slit in upper epidermis (Bladmineerders van Europa).

Hosts in Britain unknown. On Campanula and Phyteuma elsewhere. Added to the British checklist by Henshaw in Chandler, 1998. Widespread in continental Europe.

Phytomyza rapunculi Hendel, 1927 [Diptera: Agromyzidae]



Key for the identification of the known mines of British
non-Diptera recorded on Campanula


Note: The larvae of mining Coleoptera, Hymenoptera and Lepidoptera may live in a corridor mine, a corridor-blotch mine, a blotch mine, a case, a rolled or folded leaf, a tentiform mine or sandwiched between two more or less circular leaf sections in later instars. Larva may pupate in a silk cocoon. The larva may have six legs (although they may be reduced or absent), a head capsule and chewing mouthparts with opposable mandibles (see video of a gracillarid larva feeding). Larvae of Hymenoptera and Lepidoptera usually also have abdominal legs (see examples). Frass, if present, never in two rows. Unless feeding externally from within a case the larva usually vacates the mine by chewing an exit hole. Pupa with visible head appendages, wings and legs which lie in sheaths (see examples).


1a > Leaf-miner: In the first instar the larva mines the leaves, forming short, irregular, blotch-like mines, but in later instars it lives externally, feeding in spun leaves and often twisting those of tender shoots. Larval head light-brown or yellowish brown, edged with black postero-laterally, ocellar area blackish; prothoracic plate black edged with whitish anteriorly; abdomen dull dark green; pinacula distinct, black, sometimes brownish but with black bases to setae; anal plate large, black (Bradley et al., 1973). Small, full depth mine without a definite shape; little frass. Some silk is deposited in the mine. The larva soon leaves the mine and continues feeding among spun leaves (Bladmineerders van Europa).

Polyphagous. On numerous genera and species of plant families, but not yet on Campanula, in Britain. On numerous genera and species of plant families including Campanula elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae].

1b > Leaf-miner: Rather narrow corridor, untidy and sometimes branched, starting from the base of the leaf, in particular the midrib. Sides of the corridor irregularly eaten out, not really parallel. Frass mostly present, and then in a central line. The larva is capable of leaving the mine and start a new one elsewhere. These later mines are much broader, and the frass is scattered irregularly. (Bladmineerders van Europa).

Mine of Orthochaetes insignis on Prunella vulgaris
Mine of Orthochaetes insignis on Prunella vulgaris
Image: © Jean-Yves Baugnée (Bladmineerders van Europa)

Host plants unknown in Britain. On numerous genera and species in several plant families, including Campanula, elsewhere. Widespread in Britain and continental Europe.

Orthochaetes insignis (Aube, 1863) [Coleoptera: Curculionidae].



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