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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PHLEUM. Cat's-tails and Timothy. [Poaceae]


Ten species of Phleum are recorded in Britain. These include the native Sand Cat's-tail (P. arenarium), Alpine Cat's-tail (P. alpinum), Smaller Cat's-tail (P. bertolonii), Purple-stem Cat's-tail (P. phleoides) and Timothy (P. pratense). The BSBI provide a downloadable plant crib for Phleum.

Twenty-one British miners are recorded on Phleum.

Nearly 100 British miners or possible miners are recorded on grasses in Britain.

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

It is recommended that adults of all miners on grasses be reared to be certain of their identity.

Timothy (Cat's-tail grass) Phleum pratense. Image: © Linda Pitkin
Timothy (Cat's-tail grass) Phleum pratense



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


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: Long upper-surface corridor usually containing several larvae that graze shoulder to shoulder from the leaf tip downwards. Pupation outside the mine. Mines and larvae are indistinguishable from those of A. nigrella (Bladmineerders van Europa).

On Bromus, Bromopsis, Elymus, Holcus, Phleum and Triticum in Britain and additional grasses elsewhere. Widespread in Britain and continental Europe.

Agromyza mobilis Meigen, 1830 [Diptera: Agromyzidae].

1b > Leaf-miner: Larvae feed singly, forming an upper surface linear-blotch mine. Pupation either internal or external, with the puparium loosely glued to the leaf (Spencer, 1976: 91).

Oviposition near the leaf margin, at some distance from the leaf tip. From there develops an upper-surface corridor-blotch. At first the mine ascends as a narrow corridor towards the leaf tip, then the direction turns and the mine, steadily widening, descends in the direction of the leaf base. Frass irregular, in rather coarse grains. Larva solitary. Pupation mostly outside the mine; in that case the puparium often sticks to the leaf (Bladmineerders van Europa).

Mine of Agromyza albipennis on Phalaris arundinacea. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Agromyza albipennis on Phalaris arundinacea
Image: © Willem Ellis (Bladmineerders van Europa)

On Arrhenatherum, Brachypodium, Bromus, Dactylis, Glyceria, Holcus, Hordeum, Milium, Phalaris and Poa, but not yet on Phleum, in Britain and additional grasses elsewhere. Widespread and common in Britain. Also recorded in the Republic of Ireland. Very common in western Europe and recorded in Canada.

Agromyza albipennis Meigen, 1830 [Diptera: Agromyzidae].

1c > Leaf-miner: Larval leaf-mine starts as a narrow channel running towards apex of leaf but later develops into a broad blotch running downwards. Frass largely diffused, giving the mine a characteristic greenish appearance. Pupation external (Spencer, 1976: 126).

Corridor, usually several in one leaf, running from close to the leaf base up to near the tip, then reversing direction and widening, resulting in one communal mine in which the larvae descend in a common front . Frass somewhat deliquescent, mine therefore strikingly green. Pupation outside the mine. Neither mine nor larva distinguishable from those of mobilis (Bladmineerders van Europa).

Puparium reddish brown

On Dactylis, Festuca, Glyceria, Holcus, Lolium, Phleum, Poa, Secale, Setaria, Trisetum and Triticum in Britain and additionally other genera of grasses elsewhere. Widespread in Britain. Common and widespread thoughout much of Europe. Also recorded in the U.S.A.

Agromyza nigrella (Rondani, 1875) [Diptera: Agromyzidae].
1d > Leaf-miner: Larvae feeding singly, forming a long, widening mine on the upper surface of the leaf, which is generally limited to one side of the leaf. Pupation external. Puparium varying from black to reddish, glued to the leaf near the end of the mine

On Glyceria and Holcus, but not yet on Phleum, in Britain and additional genera of grasses in continental Europe. Widespread and common in Britain. Widespread in continental Europe. Also recorded in Canada.

Agromyza nigripes Meigen, 1830 [Diptera: Agromyzidae].

1e > Leaf-miner: Larva feeds mainly in the leaf sheaths. The short mines which may be formed in the leaf blade may be easily overlooked. Pupation internal (Spencer, 1976: 178).

Mine begins as a narrow, usually upper-surface, occasionally lower-surface or interparenchymatous corridor in the blade, that descends towards the ligule, thence continues into the leaf sheath, generally on its inside. Usually only one mine per leaf. Puparium in a puparial chamber at the margin of the leaf sheath. Neither mine nor larva can be distinguished from that of C. fulvipes that, as far as is known, only feeds on Poa trivialis (Bladmineerders van Europa).

On Alopecurus, Elymus, Festuca, Holcus and Phalaris, but not yet on Phleum, in Britain (including the Channel Is.) and additional grasses elsewhere. Widespread from the southern England to Scotland, most northerly record Outer Hebrides. Also recorded in the Republic of Ireland, Europe, Africa and Japan.

Cerodontha denticornis (Panzer, 1806) [Diptera: Agromyzidae].

1f > Leaf-miner: Usually a number of larvae together in a mine. Broad elongated mine; the form is dependent of the leaf form of the host plant. Frass green. Pupation in the mine

On Bromopsis, Dactylis, Elymus and Phalaris, but not yet on Phleum, in Britain and additional grasses, including Elytrigia, elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread and common in continental Europe. Also recorded in Japan, U.S.A. and Canada.

Cerodontha incisa (Meigen, 1830) [Diptera: Agromyzidae].

1g > Leaf-miner: Normally several larvae feed together. Pupation in the mine (Spencer, 1976: 198).

Broad elongated blotch. Frass greenish. Larvae generally communal. Pupation within the mine. The black puaria are individially anchored within the mine with a silken thread attached at their rear end. Distinguishable from C. incisa only by means of the larva (Bladmineerders van Europa).

On Arrhenatherum, Brachypodium, Bromus, Bromopsis, Calamagrostis, Dactylis, Deschampsia, Elymus, Festuca, Holcus, Lolium, Molinia and Phalaris, but not yet on Phleum, in Britain and additional grasses elsewhere. Widespread and common in Britain. Also recorded in the Republic of Ireland. Widespread and frequently common in much of Europe. Also recorded in Alaska and Canada.

Cerodontha pygmaea (Meigen, 1830) [Diptera: Agromyzidae].

1h > Leaf-miner: A lower surface mine. Pupation normally in the ground (Spencer, 1976: 202).

Broad, usually lower-surface corridor in the blade, generally first rising, then descending. Mostly one larva in a mine, but sometimes several mines on a leaf may merge. Frass in grains that gradually become both larger and more widely spaced. Pupation outside the mine (Bladmineerders van Europa).

On Agrostis, Arrhenatherum, Dactylis, Elymus, Festuca, Holcus and Poa, but not yet on Phleum, in Britain. On Elytrigia elsewhere. Widespread in Britain and continental Europe. Also Canada.

Cerodontha flavocingulata (Strobl, 1909) [Diptera: Agromyzidae].

1i > Leaf-miner: Upper-surface corridor, generally in the upper half of the blade, running up to the leaf tip, usually occupying more then half the width of the leaf. Frass in green stripes at either side of the corridor. Never more than one larva in a mine. Puparium within the mine, metallic black, not anchered with a string of silk (Bladmineerders van Europa).

On Ammophila and Elymus, but not yet on Phleum, in Britain and additional grasses including Elytrigia, elsewhere. Known only from Norfolk and Elgin in Britain. Widespread in continental Europe. Also recorded in Canada and the U.S.A.

Cerodontha superciliosa (Zetterstedt, 1860) [Diptera: Agromyzidae].

1j > Leaf-miner: Long, narrow, whitish mine. Pupation internal (Spencer, 1976: 453); anterior spiracles projecting through the epidermis.

Whitish, upper-surface, rather narrow corridor with comparatively large frass grains that are laying further apart than their diameter. Pupation within the mine. The anterior spiracles of the orange-brown puparium penetrate the epidermis (Bladmineerders van Europa).

Chromatomyia nigra larva,  lateral
Chromatomyia nigra larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)
Orchestes fagi larva,  dorsal
Chromatomyia nigra pupa, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

On numerous genera of grasses, including Phleum, in Britain. Widespread and common throughout British Isles and much of Europe. Also recorded in Canada, western U.S.A. and Japan.

Chromatomyia nigra (Meigen, 1830) [Diptera: Agromyzidae].

1k > Leaf-miner: Narrow whitish mine, with frass in distinct black lumps. Pupation internal

On Arrhenatherum, Holcus, Milium and Phleum in Britain and additional grasses elsewhere. Recorded in Scotland and Widespread in continental Europe. Also recorded in Canada.

Chromatomyia fuscula (Zetterstedt, 1838) [Diptera: Agromyzidae].

1l > Leaf-miner: A substantial linear mine. Pupation internal. Puparium posterior spiracles projecting through the epidermis.

Mine of Chromatomyia milii on Holcus lanatus. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Chromatomyia milii on Holcus lanatus
Image: © Willem Ellis (Bladmineerders van Europa)
Chromatomyia milii larva,  lateral
Chromatomyia milii larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)
Chromatomyia milii larva,  lateral
Chromatomyia milii larva, dorsal
Image: © Willem Ellis (Bladmineerders van Europa)

On Hierochloe, Holcus, Hordeum, Milium and Poa, but not yet on Phleum, in Britain and additional genera of grasses elsewhere. Almost certainly widespread throughout the British Isles. Also recorded in the Republic of Ireland. Widespread from Morocco through central and northern Europe.

Chromatomyia milii (Kaltenbach, 1864) [Diptera: Agromyzidae].

1m > Leaf-miner: A narrow whitish linear mine, running down the leaf from the apex, with frass in two rows of separate grains. Pupation external (Spencer, 1976: 246).

Narrow corridor from start to end, whitish, uppper- or lower-surface, genarally running downwards. Mine often along the leaf margin. Frass in distict grains of regular size, alternating along the sides of the corridor. Pupation outside the mine (Bladmineerders van Europa).

Mine of Liriomyza flaveola on Festuca gigantea. Image: © Willis Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Liriomyza flaveola on Festuca gigantea
Image: © Willis Ellis (Bladmineerders van Europa)

On Bromus, Dactylis, Holcus and Poa, but not yet on Phleum, in Britain and additional grasses elsewhere. Common and widespread throughout Britain. Also recorded in the Republic of Ireland. Common throughout much of Europe.

Liriomyza flaveola (Fallén, 1823) [Diptera: Agromyzidae].

1n > 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, but not yet on Phleum, 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].




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


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

2 > Leaf-miner and case-bearer: The young larva eats the receptacle out of a floret of Acinos arvensis, and uses the calyce as its first case. Even before the onset of winter it switches to grasses. The larva then lives in an ochraceous, bivalved, tubular leaf case of c. 9 mm, with a mouth angle of c. 25° (Bladmineerders van Europa). The case is illustrated in British Leafminers.

On Bromopsis, Dactylis, Holcus, Koeleria, Phleum and Poa in Britain and 'grass species' elsewhere. West Norfolk and West Suffolk in Britain. Unknown elsewhere.

Coleophora tricolor Walsingham, 1899 [ Lepidoptera: Coleophoridae].

3a > Leaf-miner: Tufted hair-grass and blue moor-grass are the main foodplants, the larvae forming gallery mines (UKMoths). Gradually widening corridor, running either upwards or down. All frass is deposited in the earliest part of the mine. Often 2-3 larvae in a mine; in grasses with broad leaves sometimes more than one mine in a leaf (Bladmineerders van Europa).

On Deschampsia and Sesleria, but not yet on Phleum, in Britain and Carex, Brachypodium, Calamagrostis, Deschampsia, Elymus, Festuca, Melica, Milium, Phleum, Poa and Sesleria elsewhere. Occurs in woodland habitats in England, Wales and locally in Ireland. Also recorded in the Channel Is. and the Republic of Ireland. Widespread in continental Europe.

Elachista adscitella Stainton, 1851 [Lepidoptera: Elachistidae].

3b > Leaf-miner: The larva mines from the grass tip downwards and the mine occupies half or the whole of the leaf blade width. A whitish blotch is formed with characteristic narrow streaks of frass (British leafminers). Full depth blotch, slightly inflated, descending from the leaf tip, occupying half or the entire width of the blade. The larva may move and make a new mine elsewhere. In the latter case the mines are fairly short; otherwise an entire blade may be mined out. Frass in a some narrow greyish brown streaks. Pupation outside the mine (Bladmineerders van Europa).

On Dactylis, Deschampsia and Holcus, but not yet on Phleum, in Britain plus Luzula, Agrostis, Alopecurus, Arrhenatherum, Avena, Avenula, Brachypodium, Bromus, Calamagrostis, Elymus, Festuca Koeleria, Phalaris, Phleum, Poa, Trisetum and Triticum elsewhere. Widespread in Britain, Ireland and continental Europe.

Elachista albifrontella (Hübner, 1817) [Lepidoptera: Elachistidae].

3c > Leaf-miner: In autumn the larva makes a narrow corridor a few cm in length, in which it hibernates. In March it moves to a new leaf. Here a transparent, full depth mine is made that descends from the leaf tip, and occupies the entire width of the blade. Most frass is concentrated in the oldest, highest, part of the mine. The larva may leave its mine and restart elsewhere. Pupation outside the mine

Mine of Elachista argentella on Dactylis glomerata
Mine of Elachista argentella on Dactylis glomerata
Image: © Ben Smart (British leafminers)

On Dactylis glomerata, but not yet on Phleum, in Britain. On numerous grasses including Phleum elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Elachista argentella (Clerck, 1759) [Lepidoptera: Elachistidae].

3d > Leaf-miner: Blotch in the leaf tip; the upper side is practically flat, the lower side can turn somewhat to purple. The larva may mine 2-3 leaves (Bladmineerders van Europa).

On Avenula pratense, but not yet on Phleum, in Britain and Arrhenatherum, Avena, Festuca, Avenula, Phleum and Poa elsewhere. Distibution in Britain uknown. Widespread in continental Europe.

Elachista bedellella (Sircom, 1848) [Lepidoptera: Elachistidae].

3e > Leaf-miner: The larvae feed, causing whitish mines on the blades (UKMoths). Flat, translucent mine that can either run or down; the width may vary too, can be as wide as the blade. Frass few, grey, dispersed. The larva makes several mines (Bladmineerders van Europa).

On Arrhenatherum, Festuca, Holcus and Phleum in Britain and Arrhenatherum, Festuca and Holcus elsewhere. Widespread in Britain and continental Europe. Also recorded from the Republic of Ireland.

Elachista rufocinerea (Haworth, 1828) [Lepidoptera: Elachistidae].

3f > Leaf-miner and Stem-borer: The first instar lave mines in a leaf; after that it lives as a stem borer (Bladmineerders van Europa).

Hosts in Britain unknown. On Elytrigia, Bromus, Bromopsis, PHleum, Poa, Secale and Triticum elsewhere. Widespread in Britain and continental Europe.

Ochsenheimeria vacculella Fischer von Röslerstamm, 1842 [Lepidoptera: Ypsolophidae].



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