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

N.B. Links to the latest version of 'Leafminers and plant galls of Europe' are being edited

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ASTRAGALUS. Milk-vetches and Wild Liquorice. [Fabaceae]


Seven species of Astragalus are recorded in Britain. These include the native Alpine Milk-vetch (A. alpinus), Purple Milk-vetch (A. danicus) and Wild Liquorice (A. glycyphyllos).

Eight British miners are recorded on Astragalus.

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



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


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-mine: Details unknown.

On Astragalus in British and elsewhere. Essex (Bland, 2001). Czech Republic, French mainland, Germany, Lithuania, Slovakia, Sweden (Martinez in Fauna Europaea).

Melanagromyza astragali Spencer, 1976 [Diptera: Agromyzidae].

1b > 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 Astragalus, in Britain,. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

1c > Leaf-miner: Corridor leaf-mine in leaves. An upper surface linear mine with frass in conspicuous greenish strips, largely alternating at each side of the channel (Spencer, 1976: 241).

Upper-surface, unbranched corridor, relatively broad from the start on, but only weakly widening subsequently. The fresh mine is bright green, but turns whitish, later brown, quickly. Frass in a wide green band in the centre of the corridor, with small black granules at either side. Pupation outside the mine (Bladmineerders van Europa).

Forms an upper surface mine, with the frass in a green strips (British leafminers).

Liriomyza congesta puparium
Liriomyza congesta puparium
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagous. On numerous genera of Fabaceae in Britain and elsewhere, including Astragalus, in Britain and elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland and widespread and common throughout most of Europe

Liriomyza congesta (Becker, 1903) [Diptera: Agromyzidae].

1d > Leaf-miner: A short, irregular, linear upper surface mine on any part of the leaf. Also recorded from young pods (Bland, 1997a).

Long corridor mine. As a rule the first part of the mine is lower-surface, the later part upper-surface. Often the loops are so dense that a secondary blotch is the result. Because upper- and lower-surface corridor segments often cross, the mine obtains a strange array of transparant patches. There is no association with the midrib. Frass in strings and thread fragments. Pupation outside the mine; exit slit in upper epidermis (Bladmineerders van Europa).

Mine not associated with the veins or midrib of the leaf (It is this character which enables distinction from another Agromyzid pest species - Liriomyza huidobriensis). The larvae may leave one leaf (if not large enough) and enter another leaf, via the petiole). It exits the leaf to pupate through a semi-circular slit in the upper surface of the leaf (British leafminers).

Polyphagous. On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Astragalus, in Britain. On Armoracia elsewhere. Local, probably introduced to Britain. Widespread in continental Europe particularly in Botanical Gardens and glasshouses. Also recorded in Egypt.

Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae].

1e > Leaf-miner: A narrow linear mine adjoining the leaf margin in the first instar, which later develops into an irregular blotch with conspicuous lumps of greenish frass (Spencer, 1976: 302).

The first instar larva makes a narrow upper-surface corridor along the leaf margin. After it has moulted it begins a large upper-surface blotch. Frass in conspicuous green lumps, that can run out irregularly. Pupation outside the mine (Bladmineerders van Europa).

Forms a narrow linear mine by the margin of the leaf which later develops into a blotch. The blotch has clumps of greenish frass (British leafminers).

On Astragalus and Colutea in Britain and Anthyllis, Astragalus, Cicer, Colutea, Coronilla, Cytisus, Lathyrus, Oxytropis, Securinega and Vicia elsewhere. Widespread in continental Europe.

Phytoliriomyza variegata (Meigen, 1830) [Diptera: Agromyzidae].



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


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 and case-bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tissues via a hole cut in the epidermis. From that point it eats away as much leaf tissue as it can reach without fully entering the mine. Mine does not contain frass (Coleophora species)

2

1b > Leaf-miner, but not a case-bearer: The larva lives mainly inside the mine. Mine usually contains frass. In later instars the larva may live sandwiched between two more or less circular sections cut from the leaf.

3

2a > Leaf-miner and case-bearer: The initial mine is like that of a nepticulid. The case is made form excised leaf portions, which are added to the oral end, leading to the ringed appearance. The larva causes the leaf to have white blotches. Identification cannot be made on these alone as similar blotches can be made by early instar larvae of the Common Blue butterfly (Polyommatus icarus) (British leafminers). Oviposition at the leaf underside, mostly in a vein axil. The larva begins by making a narrow winding corridor with much frass in a broad central line. The corridor reminds that of a nepticulid (but the egg has a finely reticulate surface, unlike the smooth nepticulid egg.) In the end the corridor widens into an oval blotch, usually close to the leaf margin, out of which the first case is made. The full grown larva in a greyish brown composite leaf case of about 6 mm, attached to the underside of a leaf. The oldest quarter of the case is bivalved, laterally compressed, and is at an angle of 70° with the anterior part of the case. The mouth angle is around 40° (Bladmineerders van Europa).

On Lotus, but not yet on Astragalus, in Britain, and ? Astragalus, ? Dorycnium, Lotus, ? Medicago and ? Oxytropis elsewhere. Widespread in Britain, Ireland and continental Europe.

Coleophora discordella Zeller, 1849 [Lepidoptera: Coleophoridae].

3a > 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 Astragalus, in Britain. On numerous genera and species of plant families including Astragalus elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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

3b > Leaf-miner: An irregular gallery filled with greenish frass, leading to a circular or oval blotch with blackish frass arranged in a spiral fashion. The very first part of the mine is a densely contorted corridor of about 2 mm long, that quickly turns brown. It is followed by a more or less straight corridor of c. 10 mm, entirely filled with greyish green frass. This suddenly widens into a round blotch that during its expansion overruns the earlier corridor and in the end may occupy half of a Laburnum leaflet. The frass, greenish at first, black later, is deposited in the bloth in roughly concentric arcs, glued to the upper epidermis. Pupation external, exit slit in upper epidermis

On Cytsisus, Genista, Laburnum, Lupinus and Piptanthus, but not yet on Astragalus, in Britain and Astragalus, Chamaecytisus, Genista, Laburnum, Laburnocytisus, Lupinus and Petteria elsewhere. Widespread in Britain and continental Euorpe. Also recorded in the Republic of Ireland.

Leucoptera laburnella (Stainton, 1851) [Lepidoptera: Lyonetiidae].



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