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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RUMEX. Docks and Sorrel. [Polygonaceae]


Thirteen species and numerous hybrids of Rumex are recorded as native to Britain. These include Common Sorrel (R. acetosa), Curled Dock (R. crispus), Water Dock (R. hydrolapathum), Northern Dock (R. longifolius) and Broad-leaved Dock (R. obtusifolius).

Shore Dock (R. rupestris) is protected under Schedule 8 of the Wildlife and Countryside Act, 1981.

Seven British miners are recorded on Rumex.

The scathophagid Norellisoma spinimana is a stem-borer on Rumex.

The moth Coleophora hydrolapathella is recorded feeding in the seeds of Rumex hydrolapathum (see British leafminers).

Curled Dock - Rumex crispus Image: © Linda Pitkin
Curled Dock
Rumex crispus




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




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: Large upper side blotch or blister mine, which can start with a short corridor. In small leaves the mine can be full depth in places. Often several larvae in a mine; frass irregularly scattered in large lumps. Pupation external.

The mine is illustrated in British Leafminers.

Large blotch, theoretically upper-surface, but often virtually full depth, often preceded by a short, broad corridor. Usually several larvae in a mine. The larvae can leave their mine and make a new one elsewhere. At the start of the first mine a small group of oval, whitish, egg shells. Pupation outside the mine (Bladmineerders van Europa).

On Fallopia, Persicaria, Polygonum, Rumex and possibly Begonia (record ambiguous) in Britain and in addition Begonia [Begoniaceae] and other genera of Polygonaceae elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe. Also recorded in Morocco, Algeria, Tunisia, Syria, Israel, Korea, China and Japan.

Pegomya bicolor (Wiedemann) [Diptera: Anthomyiidae].

1b > Leaf-miner: Mine without spiral or tightly wound loops. Mine shallow, dorsal or ventral, greenish in transmitted light (only in small leaves sometimes full depth, but then the frass, when corridor-like, always in separate grains). One or more egg shells at the beginning of the mine on the ventral surface of the leaf. Details of puparium unknown.

On Rumex in Britain and elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Pegomya haemorrhoum (Zetterstedt, 1838) [Diptera: Anthomyiidae].

1c > Leaf-miner: Linear mine, becoming a blotch. Two or more larvae feeding together. Frass in lines.

At the start of the mine on the leaf under surface a group of about 5 oval white egg shells (just 1 on the small leaves of Rumex acetosella). The emerging larvae initally work shoulder to shoulder in making a broad corridor. Later they split up, making a large blotch, that often is enlarged even more by fusion with other mines. The mine is practically full depth. Frass blackish-green, often deliquescent. The larvae can leave a mine and restart elsewhere. Pupation outside the mine (Bladmineerders van Europa).

The mine starts as a short corridor on the lower surface and then becomes a large upper surface blotch. Several larvae can mine together (British leafminers).

Pegomya laticornis puparium
Pegomya solennis puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On ? Oxyria, ? Polygonum and Rumex in Britain plus Emex and Persicaria elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Pegomya solennis (Meigen, 1826) [Diptera: Anthomyiidae].



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


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

On Rumex hydropathellum in Norfolk (see British leafminers).

Coleophora hydropathella Hering,1921 [Lepidoptera: Coleophoridae].

 

1b> Leaf-miner: The larva initially mines a leaf of Common sorrel (Rumex acetosa) in July and August, and then feeds externally on lower leaves until May, when it pupates in a cocoon near the ground among vegetation (UKMoths). Young larvae make a number of rather large, untidy full depth mines. The mines contain little or no frass. The lower-surface opening, by which the larva has entered the mine, is irregularly roundish. Older larvae live free on the plant (Bladmineerders van Europa). The mine is illustrated in British Leafminers.

On Rumex in Britain and elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Adscita statices (Linnaeus, 1758) [Lepidoptera: Zygaenidae].

1c > Leaf-miner: Initially a gallery is formed, this turning into a blotch, and later two successive conical leaf-rolls (UKMoths). Initially a pale, later brown, usually lower-surface blotch. The blotch is preceded by an epidermal corridor, but that may be obliterated by the later blotch. Silk at the inside of the mine causes it to buckle up a bit and fold. The reddish brown frass is accumulated in a corner of the mine. The older larva leaves the mine and continues feeding inside an untidy cone, made by cutting off a strip of leaf tissue and stitching it in place with silk (Bladmineerders van Europa).

On Fallopia, Lysimachia, Persicaria, Polygonum and Rumex in Britain and Chenopodium, Lysimachia, Lythrum, Persicaria, Oxyria, Persicaria, Polygonum and Rumex elsewhere. Occurring locally in England, Scotland and parts of Ireland. Widespread in continental Europe.

Calybites phasianipennella (Hübner, 1813) [Lepidoptera: Gracillariidae].

1d > 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).

On numerous genera and species of several plant families, including Rumex, in Britain and elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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

1e > Leaf-miner: Oviposition at the leaf underside, usually near a vein. The mine is a narrow, hardly widening, corridor that makes about 5 whole of half circles closely around the egg. The leaf tissue around th mine is intensely reddened; often several mines in a leaf. Frass in a narrow central line. The gallery starts in tight spirals, turning leaf red (British leafminers). The larva moves away in an irregular gallery (UKMoths). Pupation outside the mine (Bladmineerders van Europa). Pupation on detritus in a cocoon (British leafminers).

On Rumex in Britain and elsewhere. Widespread in southern England and continental Europe. Also recorded in the Republic of Ireland.

Enteucha acetosae (Stainton, 1854) [Lepidoptera: Nepticulidae].


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