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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AVENA. Oats and Wild-oats. [Poaceae]


Five or six species of Avena are recorded in Britain. A. fatua x sativa is the only native species. Introduced species include Oat (A. sativa), Slender Oat (A. barbata), Wild-oat (A. fatua), Winter Wild-oat (A. sterilis) and Bristle Oat (A. strigosa). The BSBI provide a downloadable plant crib for Avena.

Twenty-one British miners are recorded on Avena.

Spencer (1990) recorded the agromyzid Liriomyza orbona on Bellis perennis, although later he stated the host of L. orbona was unconfirmed, but certainly Gramineae (Spencer, 1976). Later still he gives the hosts as Avena, Deschampsia and Poa (Spencer, 1990), although it is not clear whether any of these are British host records.

The coleophorid Coleophora lixella is recorded as a seed-feeder on Avena elsewhere.

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

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

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



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


1# > ? Leaf-mine: Details unknown.

On Avena, Deschampsia and Poa (Spencer, 1990), although it is not clear whether any of these are British host records. Widepread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe

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

1a > Leaf-miner: Leaf-mine normally short and broad (Spencer, 1976: 97). According to Hering (1957) initially the larva does not feed towards the apex of the leaf. Pupation external (Spencer, 1976: 97).

The shallow, whtish mine starts (not very close to the base of the lamina) as a fine ascending corridor. This is overrun when the direction alternates, and the mine quickly widens. The final mine is characteristically short; often not the full width of the leaf is used. Frass in big black grains, never greenish. Pupation outside the mine (Bladmineerders van Europa).

On Avena, Hordeum and Secale in Britain and in addition on Elytrigia and Triticum elsewhere. Widespread, but local, in Britain. Common and Widespread in continental Europe. Also recorded in Canada and America.

Agromyza ambigua Fallén, 1823 [Diptera: Agromyzidae].

1b > 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 and Trisetum, but not yet on Avena, 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].

1c > Leaf-miner: The young larva first feeds towards the apex of the leaf, later turning and feeding downwards. Several larvae can occur together in a single leaf. Pupation external (Spencer, 1976: 130).

Upper-surface, greenish, gradually widening corridor, at first running towards the leaf tip, then reverses. Through fusion of several mines the final mine is often communal. Frass in backish green grains, often washed out. Pupation outside the mine (Bladmineerders van Europa).

Puparium reddish brown

Mine of Agromyza nigrociliata on Arrhenatherum elatius. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Agromyza nigrociliata on Arrhenatherum elatius
Image: © Willem Ellis (Bladmineerders van Europa)
Agromyza nigrociliata puparium
Agromyza nigrociliata puparium
Image: © Willem Ellis (Bladmineerders van Europa)

On Arrhenatherum, Dactylis, Elymus, Hordeum, Phalaris, Secale and Triticum, but not yet on Avena, in Britain and additional genera of grasses elsewhere. Widespread in Britain and continental Europe. Also recorded in the East Palaearctic.

Agromyza nigrociliata Hendel, 1931 [Diptera: Agromyzidae].

1d > Leaf-miner: Mine greenish with only single larva, initially running towards apex of leaf before turning back down and developing into a broad blotch. Puparium reddish brown

On Arrhenatherum, Bromus, Calamagrostis, Poa, Secale and Triticum, but not yet on Avena, in Britain and additional grasses elsewhere. Widespread in Britain and continental Europe.

Agromyza rondensis Strobl, 1900 [Diptera: Agromyzidae].

1e > 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 Secale, but not yet on Avena, 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].

1f > Leaf-miner: Narrow whitish mine, with frass in distinct black lumps. Pupation internal (Spencer, 1976: 422).

Whitish, upper-surface, descending corridor, about halfway up the blade. Frass in distinct black grains that are lying further apart than their diameter. Pupation in the mine (Bladmineerders van Europa).

On Arrhenatherum, Holcus, Milium and Phleum, but not yet on Avena, in Britain and additional grasses elsewhere. Recorded in Scotland and Widespread in continental Europe. Also recorded in Canada.

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

1g > Leaf miner: A substantial linear mine. Pupation internal; posterior spiracles projecting through the epidermis (Spencer, 1976: 449).

Elongated, shallow, upper-surface or lower-surface blotch, not infrequently several in one leaf. Frass in strings or pearl chains. Pupation within the mine (Bladmineerders van Europa)

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 Avena, in Britain and additional genera of grasses, including Agrostis, 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].

1h > Leaf-miner: A short narrow mine, generally near apex of leaf. Larva with each segment bearing a row of characteristic papilli which are retained in the puparium (Spencer, 1976: 328). Pupation internal.

Transparent, short and narrow mine not far from the leaf tip. Frass in two rows of grains. Pupation outside the mine (Bladmineerders van Europa).

On Avena, Dactylis, Holcus, Hordeum, Lolium, Phalaris, Phragmites, Poa and Secale in Britain and additional other genera of grasses elsewhere. Widespread, but local, in south of Britain. Widespread in continental Europe. Also recorded in Canada.

Pseudonapomyza atra (Meigen, 1830) [Diptera: Agromyzidae].

1i > 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 pupariuml 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 Avena, in Britain (including the Channel Is.) and additional grasses, including Avena, 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].

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

On Bromopsis, Dactylis, Elymus and Phalaris, but not yet on Avena, in Britain and additional grasses, including Avena, 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].

1k > 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 Avena, 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].

1l > 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

On Ammophila and Elymus, but not yet on Avena, in Britain and additional grasses including Avena, 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].

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 Avena, 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.

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 Avena, 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 Avena


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/Stem miner: The larvae mine the stems of various coarse grasses (UKMoths; Plant in Pitkin & Plant, 2005).

The larva mines just a few days in the leaf, then continues as a stem borer on the lower part of the stem. They regularly move to a new stem. The central leaves of the infested plants wither and die (Bladmineerders van Europa).

On Dactylis and Poa, but not yet on Avena, in Britain and Alopecurus, Avena, Bromus; Dactylis, Hordeum, Poa, Secale and Triticum elsewhere. Widespread in England and Wales. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Ochsenheimeria taurella (Denis & Schiffermüller, 1775) [Lepidoptera: Ypsolophidae].

1b > 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 Avena, 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].

1c > 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 Avena, in Britain and Arrhenatherum, Avena, Festuca, Avenula, Phleum and Poa elsewhere. Distribution in Britain uknown. Widespread in continental Europe.

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

1d > Leaf-miner: The mine begins near the leaf tip and descends towards the base. The mine occupies the entire width of the blade. Frass initially scattered, later in an irregular central line. Fully developed mine c. 8 cm long. Probably the larva is capable of leaving its mine and restarting in another leaf. Pupation external (Bladmineerders van Europa).

On Calamagrostis epigejos, but not yet on Avena, in Britain and Avena, Calamagrostis, Glyceria, Phalaris and Poa elsewhere. Cambridge and East Norfolk in Britain. Widespread in continental Europe.

Elachista pomerana Frey, 1870 [Lepidoptera: Elachistidae].

1e > Leaf-miner: Mines downwards from leaf tip to stem. Makes a long narrow yellowish mine. May be up to four larvae in one leaf (British leafminers). Long narrow yellowish corridor, descending from the leaf tip to its base; at times 3-4 larvae in a leaf. Often several larvae in a communal mine. Pupation outside the mine (Bladmineerders van Europa).

On Carex, Agrostis, Brachypodium, Deschampsia and Festuca, but not yet on Avena, in Britain and Agrostis, Avena, Brachypodium, Calamagrostis, Festuca, Milium and Poa elsewhere. Widespread in Britain and continental Europe.

Elachista stabilella Stainton, 1858 [Lepidoptera: Elachistidae].

1f > Leaf-miner: Narrow, flat, corridor descending from the leaf tip. Frass in an almost continuous line. The larva usually makes several mines. Mines pale yellow green at first, turning purple later. Pupation external (Bladmineerders van Europa).

On Bromopsis erecta and Avenula pubescens, but not yet on Avena, in Britain and Avena, Bromopsis, Calamagrostis, Dactylis, Festuca, Avenula and Holcus elsewhere. Southern England. Widespread in continental Europe.

 

Elachista subnigrella Douglas, 1853 [Lepidoptera: Elachistidae].



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