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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HERACLEUM. Hogweeds. [Apiaceae]


Three species of Heracleum are recorded in Britain. These include the native Hogweed (H. sphondylium) and Giant Hogweed (H. mantegazzianum).

Twelve or thriteen British miners are recorded on Hearcleum.

British records of Pegomya solennis (= versicolor) on Heracleum are discounted by Griffiths (1982) as probable misidentifications of the tephritid Euleia heraclei.

The agromyzid Melanagromyza angeliciphaga is recorded boring stems of Heracleum and other Apiaceae in Britain and elsewhere.

Elsewhere the agromyzid Liriomyza lutea is recorded feeding in the seed heads of Heracleum.

Elsewhere the agromyzid Napomyza carotae is recorded on Apium. In larval transfer experiments in Switzerland found that the larvae of Napomyza carotae developed normally in Apium, Heracleum, Pastinaca and Petroselinum.

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

Hogweed - Heracleum sphondylium. Image: © Brian Pitkin
Hogweed
Heracleum sphondylium



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


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.


1# > Leaf-mine: Details of mine unknown.

On Heracleum in Britain. Also continental Europe (Martinez in Fauna Europaea).

Melanagromyza limata Spencer, 1971 [Diptera: Agromyzidae].

1a > Stem miner: An external mine on stem or leaf stalk. Pupation either at leaf base or beneath epidermis of main stem (Spencer, 1972b: 31).

On Heracleum in Britain and continental Europe. Widespread in south, but not common, in Britain. Widespread in continental Europe.

Ophiomyia heracleivora Spencer, 1957 [Diptera: Agromyzidae].

1b > Leaf miner

2

2a > Leaf miner: Interparenchymal mine

3

2b > Leaf miner: Mine not interparenchymal

4

3a > Leaf miner: A regular greenish inter-parenchymal blotch mine, frequently delimited by two veins, appearing somewhat mottled as a result of small deeper areas of feeding through the upper parenchyma (Spencer, 1972b: 78 (fig. 259); Spencer, 1976: 428, 429 (fig. 748).

The mine starts with a quite inconspicuous lower-surface corridor that soon changes into an extensive interparenchymatous blotch. The upper cell layer of the palisade parenchyma is eaten away in many places, giving the mine in transparency a perforated appearance. Fresh mines are pale green, later they turn brown; they give the leaves a strikingly diseased impression. Feeding lines absent, frass grains strikingly few. Larvae solitary. Pupation outside the mine, exit slit in lower epidermis (Bladmineerders van Europa).

Forms a blotch mine between two veins, having a characteristic sieve-like appearance (where the larva has fed through the upper parenchyma). Pupation outside the mine. (British leafminers).

Phytomyza heracleana puparium
Phytomyza heracleana puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Heracleum in Britain and this and other Apiaceae elsewhere including Heracleum in Britain. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Phytomyza heracleana Hering, 1937 [Diptera: Agromyzidae].

3b > Leaf miner: Mine inter-parenchymal, greenish-yellow, not always readily visible, an irregular linear-blotch (Spencer, 1972b: 78 (fig. 260)).

Broad, irregular interparenchymatous corridor, here and there widening into a blotch; fairly inconspicuous. Frass grains few, irregularly scattered. Pupation outside the mine (Bladmineerders van Europa).

The leaf discolours as the larva mines through the parenchyma of the leaf. The mine is inter-parenchymal, greenish-yellow, not always readily visible, an irregular linear-blotch (British leafminers).

Mine of Phytomyza sphondyliivora on Heracleum. Image: © Rob Edmunds (British leafminers)
Mine of Phytomyza sphondyliivora on Heracleum
Image: © Rob Edmunds (British leafminers)

On Heracleum, in Britain and elsewhere. Widespread in England. Also recorded in continental Europe.

Phytomyza sphondyliivora Spencer, 1957 [Diptera: Agromyzidae].

3c > 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 Heracleum, in Britain,. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

4a > Leaf miner: A large blotch, yellow or brown, preceded by a short corridor that in the end mostly is completely overrun. Generally several larvae share a mine. Especially in fresh mines the green primary and secondary feeding lines are well visible. Pupation outside the mine. Puparium yellow.

Euleia heraclei puparia
Euleia heraclei pupariria
Image: © Willem Ellis (Bladmineerders van Europa)

Polyphagous. On numerous genera of Apiaceae and possibly some Asteraceae, including Heracleum, in Britain and elsewhere. Throughout the British Isles. Also recorded in the Republic of Ireland and most of the Palaearctic region, as far east as Afghanistan.

Euleia heraclei (Linnaeus, 1758) [Diptera: Tephritidae].

4b > Leaf miner: A large blotch, yellow or brown, preceded by a short, in the end mostly unrecognisable corridor. Generally several larvae in the mine. Especially in fresh mines the green primary and feeding lines area well marked. Pupation outside the mine.

On Angelica and possibly Arctium and Heracleum in Britain. Widespread but very rare in Britain. Also recorded in the Republic of Ireland and throughout Europe, except in the south.

Cryptaciura rotundiventris (Fallén, 1814) [Diptera: Tephritidae].

4c > Leaf-miner: Larva forms an upper surface primary blotch with several larvae feeding together; the blotch is greenish when fresh but becomes yellowish with age (Spencer, 1972b: 78 (fig. 257); Spencer, 1976: 376, 377 (fig. 655)).

Round or oval blotch, green at first, later yellowish. Young mine are interparenchymatous, only the older mines are truly full depth. Generally several larvae in a communal mine. Pupation outside the mine. Exit slit in lower epidermis (Bladmineerders van Europa).

A conspicuous, yellowish, almost circular upper surface blotch. Normally several mines on a leaf which may run together giving the impression of a single mine (British leafminers).

On Aegopodium and Angelica, but not yet on Heracleum, in Britain and elsewhere and Laserpitium elsewhere. Widespread throughout Britain and continental Europe. Also recorded in U.S.A. and Canada.

Phytomyza angelicae Kaltenbach, 1872 [Diptera: Agromyzidae].

4d > Leaf miner: Corridor mine.

5

5 > Leaf miner: A conspicuous, whitish linear mine. Pupation external (Spencer, 1976: 506, 507 (fig. 886)).

Long, upper-surface, frequently branched, little widening corridor; sides somehwat irregular. Often several mines in a leaf. Frass in grains that are placed close together, rarely forming short pearl chains. Pupation outside the mine, exit slit in lower epidermis. Sometime the puparium sticks to the leaf. Feeding punctures in lower epidermis (Bladmineerders van Europa as Phytomyza pastinacae / spondylii).

Larva forms a conspicuous, whitish linear mine. Larva leaves the mine through the lower surface and falls from the leaf on pupation (British leafminers).

Orchestes fagi larva,  dorsal
Phytomyza pastinacae / spondyli puparium
Image: © Willem Ellis (Bladmineerders van Europa)

Most records require confirmation, since the two names have been treated as synonyms and distinct species. On ? Astrantia, ? Heracleum and ? Pastinaca in Britain and Heracleum, Levisticum and Pastinaca elsewhere. Widespread and common throughout the British Isles. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Phytomyza spondylii Robineau-Desvoidy, 1851 [Diptera: Agromyzidae]
OR
Phytomyza pastinacae Hendel, 1923 [Diptera: Agromyzidae].


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


 

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 several plant families, including Heracleum, in Britain and elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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

1b > Leaf miner: The larvae are often gregarious and feed on the underside of the leaf causing a 'windowing' effect as they eat the mesophyll and lower epidermis. This effect can be seen from the top of the leaf as it discolours (British leafminers). Short, small, irregular, sometimes widened corridor. Mostly a number in a leaf, concentrated in the axils of the midrib and the primary side veins. Each larva makes a number of mines. Often the larva protrudes with its rear end out of the mine, causing most frass to be ejected. While moving, at the leaf underside, silken threads are produced, in wich grains of frass may be trapped. Older larvae live free and cause window feeding, often in a group under a light spinning (Bladmineerders van Europa).

Polyphagous. On Angelica sylvestris, Anthriscus sylvestris, Daucus carota, Heracleum sphondylium and Heracleum sativain Britain and Aegopodium podagraria, Angelica archangelica subsp. litoralis, Angelica sylvestris, Anthriscus caucalis, Anthriscus cerefolium, Anthriscus sylvestris, Apium graveolens, Berula erecta, Carum carvi, Chaerophyllum hirsutum, Chaerophyllum temulum, Cicuta virosa, Conium maculatum, Daucus carota, Heracleum sphondylium, Levisticum officinale, Oenanthe, Pastinaca sativa, Peucedanum, Pimpinella saxifraga, Seseli libanotis, Silaum, Sium latifolium, Sison amomum and Torilis elsewhere. Widespread in Britain and continental Europe.

Epermenia chaerophyllella (Goeze, 1783) [Lepidoptera: Epermeniidae].


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