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

 

SYMPHORICARPOS. Snowberry and Coralberry. [Caprifoliaceae]


Three species of Symphoricarpos have been introduced to Britain. All are introduced and include Snowberry (S. albus) and Coralberry (S. orbiculatus).

Twelve British miners are recorded on Symphoricarpos.

Elsewhere the tephritid Philophylla caesio is recorded as a miner in the petioles of Urtica sp. by Ferrar (1987), Beiger (1968) and White (1988), although there are unconfirmed records on Caprifoliaceae and Asteraceae, which seems an odd combination of hosts.

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

Snowberry - Symphoricarpos rivularis. Image: © Brian Pitkin
Snowberry
Symphoricarpos rivularis



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


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, at least initially, star shaped. Pupation internal.

2

1b > Leaf-miner: Mine long and often white and sinuous. Pupation external.

3

2a > Leaf-miner: Mine star shaped when small, sometimes with a longer linear section, later an irregular brownish blotch. Pupation internal (Spencer, 1976: 466).

Mine not associated with the midrib, stellate, with a large number of short upper-surface corridors. The mine looks greyish and is inconspicuous. Frass in discrete grains. One, sometimes two larvae in a mine. Pupation within the mine.

Forms an upper surface mine which is normally blotchy. The young mine is stellate. The initial mine is purple in colour - turning brown as it ages.

Chromatomyia periclymeni puparium
Chromatomyia periclymeni puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Lonicera periclymenum, Lonicera xylosteum, Leycesteria formosa and Symphoricarpos albus in Britain and additional other species of Lonicera elsewhere.

Chromatomyia periclymeni (Meijere, 1924) [Diptera: Agromyzidae].

2b > Leaf-miner: The very first part of the mine is a quite inconspicuous, lower-surface epidermal corridor, that ends upon the midrib. Then the larva [usually] bores in the midrib, from where it makes long upper-surface corridors. Often the latest corridor that is made is much longer than the others, and follows the leaf outline in a loose loop. Frass in long strings at the extreme side of the mine. Pupation in the mine, in a lower-surface puparial chamber.

[Usually] initially on the mid-rib from which there may be several short narrow galleries into the leaf. In the main gallery there may be alternate lower surface and upper surface stretches. Frass in conspicuous long streaks.

A winter form not associated with the midrib and with a mine that meanders thoughout the leaf probably represents this species. Frass in long strings at the extreme side of the mine. Pupation in the mine, in a lower-surface puparium chamber

On Lonicera periclymenum, Symphoricarpos albus and Leycesteria in Britain and additional species of Lonicera and Symphoricarpos elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in western and south western Europe.

Chromatomyia aprilina (Goureau, 1851) [Agromyzidae].

2c > Leaf-miner: Mine an irregular stellate blotch with a later linear section. Pupation internal; firmly glued within the mine by frass (Spencer, 1976: 443).

The mine begins with a few lower-surface corridors, radiating from one centre that is not associated with the midrib; the corridors are very shallow and not easy to observe. Subsequently some (rarely only one) upper-surface, rather long and often branched corridors are formed from the same centre. Frass mostly at one side, in pearl chains. Pupation within the mine.

An upper surface gallery with a star-shaped start. Frass in pearl-strings.

Chromatomyia lonicerae larva,  lateral
Chromatomyia lonicerae larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

On Lonicera periclymenum and Symphoricarpos albus in Britain and additional species of Lonicera elsewhere. Widespread in south of Britain. Also recorded in the Republic of Ireland. Widespread in much of Europe.

Chromatomyia lonicerae (Robineau-Desvoidy, 1851) [Diptera: Agromyzidae].

3a > Leaf-miner: A long white mine. Pupation external (Spencer, 1972b: 62 (fig. 209), 65, as lonicerae).

Strongly widening, upper-surface, unbranched corridor; its first section usually follows the leaf margin for some distance. Pupation outside the mine; exit slit in upper epidermis.

Leaf mine is formed in the young tender leaf. Larva forming long white mine which widens.

Aulagromyza cornigera puparium
Aulagromyza cornigera larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)
Aulagromyza cornigera puparium
Aulagromyza cornigera puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Lonicera periclymenum, Leycesteria formosa and Symphoricarpos albus in Britain and elsewhere. The Netherlands, Germany, French mainland, Poland and Spanish mainland in continental Europe.

Aulagromyza cornigera Griffiths, 1973 [Diptera: Agromyzidae].

3b > Leaf-miner: A long conspicuous white linear mine. Pupation external (Spencer, 1976: 315, 317 (fig. 565)).

An upper-surface corridor that widens only a little, and generally is unbranched. Often a part of the corridor loosely follows the leaf margin. Frass in two neat rows of grains or short thread fragments. Pupation outside the mine. Feeding punctures in the lower surface (always?).

An upper surface gallery with frass in large, well-spaced grains.

Aulagromyza hendeliana puparium
Aulagromyza hendeliana
larval. lateral
Image: © Willem Ellis (Bladmineerders van Europa)
Aulagromyza hendeliana puparium
Aulagromyza hendeliana puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Lonicera periclymenum and Symphoricarpos albus in Britain and additional species of Lonicera elsewhere. Common in southern England. Also recorded in the Republic of Ireland. Widespread in much of Europe.

Aulagromyza hendeliana (Hering, 1926) [Diptera: Agromyzidae].

3c > Leaf-miner: Mines similar to A. hendeliana but darker (British leafminers), filled centrally with dark-green frass (Spencer, 1976: 318).

Little widening, upper-surface corridor, generally unbranched and not associated with the leaf margin. Frass in a broad green band with scattered dark granules, sometimes locally with ill-defined strikes. Pupation outside the mine; exit slit in upper epidermis.

On Lonicera etrusca and Symphoricarpos albus in Britain and additional species of Lonicera elsewhere. Recorded as new to Britain from Hants and subsequently recorded from Kent. Widespread in continental Europe.

Aulagromyza luteoscutella (de Meijere, 1924) [Diptera: Agromyzidae].



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

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: Lobe case. The full grown case is about 7 mm long. The mouth angle is 0°, causing the case to lie flat on the leaf. The case is gradually enlarged by the addition of rings that are cut out of the epidermis. The rings become gradually larger, and stick irregularly out of the contour of the case. The rings are cut out of the lower epidermis of the mine. This implies that mines may have both normal, small openings, and large ones. Compare for instance C. violacea, that cuts rings out of the upper epidermis. The larva feeds briefly initially and again after over wintering. It then aestivates until Autumn. It makes one case which it enlarges by adding pieces of excised lower epidermis.

On Cornus, Frangula, Lonicera, Rhamnus, Symphoricarpos and Viburnum in Britain and Cornus, Frangula, Lonicera, Rhamnus, Swida, Symphoricarpos and Viburnum elsewhere. Southern England. Widespread in continental Europe.

Coleophora ahenella Heinemann, 1877 [Lepidoptera: Coleophoridae].

2b > Leaf-miner and case-bearer: The larva feeds on a wide range of trees, shrubs and herbs, favouring Rosaceae, but not exclusively. The fully developed cased larva may be found active in October and again, after winter diapause, in April. Cases, about 6 mm, of diapausing larvae may be found through winter, fixed to a tree or fence post. The dorsal surface of the case is usually covered in leaf fragments, but they can sometimes be worn off almost smooth. The ventral surface is swollen at the middle and has a keel, which usually bends upwards at the posterior. The cases of C. ahenella (on Rhamnus, Frangula, Viburnum and Cornus) and C. potentillae (case less swollen, keel not bent up, resting position less prone) are very similar. Brownish lobe case that lies almost flat on the leaf, either on the upper or on the lower side. Case widest about the middle. Ventrally there is a distinct keel. Mouth angle 0°. Full depth mines rather large. The flaps of cuticular tissue that serve to enlarge the case are cut out of the upper epidermis. (contrary to C. ahenella and C. potentillae, that use tissue from the lower epidermis). The removal of these tissue flaps creates holes that are much larger than those that serve as the entrance to the mine.

Coleophora violacea larva,  lateral
Coleophora violacea larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagous. On numerous genera and species in several plant families, but not yet on Symphoricarpos, in Britain. On numerous genera and species in several plant families, including Symphoricarpos, elsewhere. Widespread in Britain and continental Europe.

Coleophora violaceae (Ström 1783) [Lepidoptera: Coleophoridae].

3a > Leaf-miner: Larvae usually gregarious. Early mine an epidermal gallery leading to a contorted blotch with black frass. Subsequently two successive cones formed by folding the tip of a leaf downwards (British leafminers, as Caloptilia syringella). Often, many leaves on a single bush turn brown and curl up with the mines. The species can be a pest in gardens. The mine begins at a row of eggs along the midrib. The emerging larvae form relatively broad, inconspicuous, lower-surface corridor. Subsequently a large, grey brown or greenish brown, very opaque upper-surface blotch is made, occupied by ten or more larvae. The mine makes the leaf somewhat bumpy, but the leaf does not fold around the mine, like in Caloptilia cuculipennella. After some time the larvae leave the mine and continue feeding, still comunnally, in a downwards rolled leaf.

Gracillaria syringella larva
Gracillaria syringella larva
Image: © Willem Ellis (Bladmineerders van Europa)

On Symphoricarpos, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa in Britain and Chionanthus, Forestiera, Forsythia, Fraxinus, Jasminum, Ligustrum, Phillyrea and Syringa elsewhere. Widespread in Britain, Ireland and continental Europe.

Gracillaria syringella (Fabricius, 1794) [Lepidoptera: Gracillariidae].

3b > Leaf-miner: Forms a large transparent blotch mine - with a central spot, where the frass collects. This spot is usually red-brown. Brownish, full depth, inflated blotch, usually at the leaf margin, often with a central brown spot. Oviposition at the leaf underside. Often 2-3 larvae in a mine. Pupation outside the mine. Pupation on the bark in a cocoon.

On Lonicera, but not yet on Symphoricarpos, in Britain and Lonicera and Symphoricarpos elsewhere. Widespread in southern England and Wales. Widespread in continental Europe.

Perittia obscurepunctella (Stainton, 1848) [Lepidoptera: Elachistidae].

3c > Leaf-miner: The mine is large, occupying most of leaf. The lower epidermis with several strong creases. Lower-surface, white, inflated tentiform mine, that may occupy the entire leaf. The mine causes the leaf to roll lengthwise (the folds in the lower epidermis run from leaf base to tip). Pupa in a tough, papery cocoon; in fresh mines its colour is olive green, later it changes into pale brown.

On Leycesteria, Lonicera and Symphoricarpos in Britain and Lonicera and Symphoricarpos elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Phyllonorycter emberizaepenella (Bouché, 1834) [Lepidoptera: Gracillariidae].

3d > Leaf-miner: The mine is usually underside, often twisting leaf into a cone. The mines can be quite abundant where it is found. Lower surface tentiform mine between leaf margin and midrib; the mine contracts diagonally, causing the leaf to roll transversely or into a pepper box.

On Leycesteria, Lonicera and Symphoricarpos in Britain and Lonicera and Symphoricarpos elsewhere. Widespread in Britain, Ireland and continental Europe.

Phyllonorycter trifasciella (Haworth, 1828) [Lepidoptera: Gracillariidae].



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