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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VERONICA. Speedwells. [Scrophulariaceae]


Forty species of Veronica are recorded in Britain. Seventeen of these are native. The BSBI provide a downloadable plant crib for Veronica.

Spiked Speedwell (V. spicata) and Fingered Speedwell (V. triphyllus) are protected under Schedule 8 of the Wildlife and Countryside Act, 1981.

Six British miners are recorded on Veronica.

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

 

Garden Speedwell - Veronica longifolia. Image: © Brian PitkinGarden Speedwell
Veronica longifolia



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


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 > Leaf-miner: Mine normally begins along margin of leaf, sometimes later developing into a secondary blotch. Pupation takes place on the lower surface of the leaf, with the anterior spiracles normally projecting through the epidermis (Spencer, 1972b: 82, 83 (fig. 271).

Wide upper-surface corridor. The first part closely follows the leaf margin. Later the margin is released, often then the corridor is so densely wound that a secondary blotch is formed. Finally a short short stretch is made that ends in a lower-surface puparial chamber. Frass in isolated grains or pearl chains (Bladmineerders van Europa).

Forms a narrow mine which follows the leaf margin, then turns and forms a secondary blotch. Pupation is in the mine (British leafminers).

on Veronica in Britain and continental Europe. Widespread in Britain and much of Europe. Also present in the U.S.A. and Canada, almost certainly as an introduction.

Phytomyza crassiseta Zetterstedt, 1860 [Diptera: Agromyzidae].
1b > Leaf-miner: Irregular mine, locally shallow, elsewhere much deeper, giving it a mottled appearance. In broadleaved plants the mine often begins as a blotch with stellate extensions, but sometimes as a very fine, shallow corridor. In grasses the mine often begins in the leaf sheath. The frass is very fine-grained, initially scattered, later in aggregates. The egg is deposited on the plant surface, and the empty egg shell remains visible. But the larvae are able to leave their mine and restart elsewhere, thus mines without an egg shell can be found as well. The larva also leaves the mine before pupation. Pupation takes place in a newly made, small, blotch mine without frass; this mine may be made in another plant (species) (Bladmineerders van Europa).

Mine of Hydrellia griseola on Glyceria fluitans. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Hydrellia griseola on Glyceria fluitans
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagpus. On ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum, ? Lychnis, ? Stellaria, ? Carex, ? Cyperus, ? Scirpus, ? Hydrocharis, ? Stratiotes, ? Lamium, ? Lemna, ? Allium, Arrhenatherum, ? Polygonum, ? Potamogeton, ? Veronica, ? Typha in Britain.

On ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum, Lychnis, ? Stellaria, Carex, ? Scirpus, Trifolium, ? Hydrocharis, Lamium, ? Lemna, Allium, Papaver, Agrostis, Alopecurus, Apera, Arrhenatherum, Avena, Avenula, Brachypodium, Briza, Bromus, Calamagrostis, Dactylis, Desmazeria, Digitaria, Echinochloa, Eleusine, Elymus, Festuca, Gaudinia, Glyceria, Holcus, Hordeum, Lagurus, Lolium, Panicum, Phalaris, Phleum, Phragmites, Poa, Secale, Setaria, Triticum, ? Polygonum, ? Potamogeton, Veronica, ? Typha and Verbena elsewhere. Widespread in England. Also recorded in the Republic of Ireland. Widespread in the Palaearctic region. Also recorded from Nearctic and Australasian Regions.

Hydrellia griseola (Fallén, 1813) [Diptera: Ephydridae].

1c > 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, but not yet on Veronica, in Britain,. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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



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


1a > Leaf-miner: Rather long corridor winding through the leaf, regularly crossing itself. The corridor later widens considerably. Frass normally in a narrow central line, but may also lie along the side, or be absent. The larva regularly leaves a mine and restarts elsewhere (Bladmineerders van Europa).

On Lamiastrum galeobdolon and Lamium album, but not yet Veronica, in Britain plus Ajuga reptans, Clinopodium vulgare, Lamium, Prunella, Stachys, Teucrium, Plantago major, Veronica, chamaedrys and Veronica longifolia elsewhere. Widespread in England and continental Europe.

Apteropeda globosa (Illiger, 1794) [Coleoptera: Chrysomelidae].

1b > Leaf-miner: Rather long full depth corridor that winds freely through the leaf and may cross itself. In the end the corridor widens considerably. Frass mostly in a narrow central line, but may also be deposited along the sides or be missing. The larvae regular leave a mine to restart elsewhere. Pupation outside the mine. Neither larva or mine can be distinguished from that of related species (Bladmineerders van Europa).

Polyphagous. On numerous genera and species in several plant families, including Veronica, in Britain and elsewhere. Widespread in Britain and continental Europe.

Apteropeda orbiculata (Marsham, 1802) [Coleoptera: Chrysomelidae].

1c > 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 Veronica, elsewhere. Recorded in southern England. Widespread in continental Europe.

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



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