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

 

OSTRYA. [Betulaceae]


One species of Ostrya is recorded in Britain.

Eleven British miners are recorded on Ostrya.

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



Key for the identification of the known mines of British
insects (Diptera and non-Diptera) recorded on Ostrya


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)

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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.

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2 > Leaf-miner and case-bearer: The larva feeds by inserting its head into small mines it creates on the leaves of birch, elm, alder, or hazel. Occasionally it is found feeding on other trees, or on herbaceous plants onto which it has accidentally Fallén. It forms two cases during its larval life. The first case is initially curved, smooth, laterally compressed with a bivalved anal opening, and about 2 mm long in September. During October it feeds, and adds a few rough collars of larval material around the oral opening. After hibernation, it feeds again in April and early May, adding more protruding collars until they equal or exceed the original smooth part of the case. At the same time, it expands the case girth by the creation of a silk gusset ventrally. The second case, 6 or 7 mm long, is formed in May, leaving the vacated first case attached to its last feeding mine. The new case is tubular with a trivalved crimp at the anal opening. The dorsum is formed from the edge of the leaf from which the case was cut. This results in a more or less serrated dorsal keel, depending on the plant species and the individual piece of leaf used. Considerable variation in the degree of serration can be found, even among specimens off the same tree. The case colour varies with food plant, from yellowish brown on birch, darkening through elm and hazel to dark brown on alder. The strongly curved young case is is a composite leaf case, the adult case is a tubular leaf case. The adult case is bivalved, about 7 mm in length; the mouth angle is around 30°. The case is straw coloured and almost always has a toothed dorsal keel (remnant of the margin of the leaf from which the case was cut). Neither larvae or cases of C. coracipennella, prunifoliae, serratella and spinella can be separated; from serratella.

On Alnus, Betula, Corylus, Ulmus and Sorbus, but not yet on Ostrya, in Britain plus Carpinus, Mespilus, Ostrya, Hippophae, Ribes, Myrica, Forsythia, Amelanchier, Chaenomeles, Cotoneaster, Crataegus, Cydonia, Eriobotrya, Malus, Prunus, Sorbus, Spiraea, Populus and Salix elsewhere. This is probably the commonest species of British coleophorid, and is found throughout the British Isles. Widespread in continental Europe.

Coleophora serratella (Linnaeus, 1761) [Lepidoptera: Coleophoridae].

3a > Leaf-miner: The larva starts making a corridor of a few mm, followed, and mostly overrun, by a circular blotch of 4-5 mm diameter. Generally several larvae feed in a single leaf, creating a distinctive pattern of feeding windows. The larvae then cut out circular cases and drop to the leaf-litter to continue feeding, leaving behind a leaf containing many circular or oval cut-outs.

On Alnus, Betula, Carpinus, Corylus, Malus and Tilia, but not yet on Ostrya, in Britain. On several genera and species in several plant families, including Ostrya, elsewhere. Fairly well-distributed throughout much of the British Isles, though it tends to be commoner further north. Widespread in continental Europe.

Incurvaria pectinea Haworth 1828 [Lepidoptera: Incurvariidae].

3b > Leaf-miner: The larva feeds on hazel or hornbeam, creating blotches with intertwining threads of frass, typical of the genus. Large white blotch, starting at the leaf margin. Frass in long threads. Often several larvae in a mine. Pupation outside the mine.

On Carpinus and Corylus, but not yet on Ostrya, in Britain plus Alnus and Ostrya elsewhere. Widespread in England and recorded in the Republic of Ireland. Widespread in continental Europe.

Eriocrania chrysolepidella (Zeller, 1851) [Lepidoptera: Eriocraniidae].

3c > Leaf-miner: The initial mine expands to form a full depth blotch. It resembles Phyllonorycter tenerella, but has a mottled lower surface. It then forms two folds. Small, angular, full depth blotch, often in a vein axil. Lower, in the end also upper, epidermis brown. The larva deposits some silk in the mine, but the quantity is so low that the mine remains practicaly flat. Later the larva leaves the mine and continues feeding within a downfolded leaf margin or leaf tip.

On Carpinus betulus, but not yet on Ostrya, in Britain. On Acer platanoides, Acer pseudoplatanus, Carpinus betulus, Carpinus orientalis and Ostrya carpinifolia elsewhere. South-east England. Widespread in continental Europe.

Parornix carpinella (Frey, 1863) [Lepidoptera: Gracillariidae].

3d > Leaf-miner: The mine is upper side, over veins. Silvery, with brown speckling, later contracting to cause leaf to fold upwards. There may be several mines on each leaf. Upper-surface silvery tentiform mine. For some time the mine remains quite flat, and appears as a blotch mine. In the final stage the leaf is strongly contracted, however. Not infrequently several mines in a leaf. Pupa in a cocoon in a corner of the mine, frass heaped in the opposite corner.

On Corylus, but not yet on Ostrya, in Britain and Corylus and Ostrya elsewhere. Widespread in Britain, Ireland and continental Europe.

Phyllonorycter coryli (Nicelli, 1851) [Lepidoptera: Gracillariidae].

3e > Leaf-miner: The mine is upper side, over veins. Silvery, with brown speckling, later contracting to cause leaf to fold upwards. Upper-surface tentiform mine. The early mine is roundish, silvery, flat, and lies centered over a side vein. The older mine strongly contracts and sometimes almost doubles the leaf.

On Carpinus betulus, but not yet on Ostrya, in Britain and Carpinus betulus and Ostrya carpinifolia elsewhere. A local species, mainly found in the south and south-east of England northwards to the midlands and South York, the most northerly record to date. Widespread in continental Europe.

Phyllonorycter esperella (Goeze, 1783) [Lepidoptera: Gracillariidae].

3f > Leaf-miner: The mine is oval on Quercus ilex (note - there may be several mines in the leaf), and similar to P. quercifoliella on deciduous oaks. It is between adjacent veins on beech and hornbeam. Small, oval, lower-surface tentiform mine, 9-14 mm long, mostly between two lateral veins. The lower epidermis with a single sharp fold (sometimes forked near its end). Pupa in very flimsy cocoon, that contains a bit of frass laterally and at the rear end.

On Betula, Carpinus, Castanea, Fagus, Nothofagus, Quercus, Malus, Ostrya and Prunus in Britain and Carpinus, Castanea, Fagus, Quercus, Prunus and Tilia elsewhere. Widespread in Britain, Ireland and continental Europe.

Phyllonorycter messaniella (Zeller, 1846) (Lepidoptera: Gracilariidae)

3f > Leaf-miner: A mine between veins from midrib to leaf-edge, narrow, tubular, with one crease in lower epidermis. Narrow, finally tubular lower-surface mine between two side veins. The lower epidermis with one strong fold. Pupa in a flimsy cocoon in a corner of the mine, usually in the axil of midrib and side vein. Frass loosely heaped in the opposite corner.

On Carpinus, but not yet on Ostrya, in Britain and Carpinus and Ostrya elsewhere. Southern half of England. Widespread in continental Europe.

Phyllonorycter tenerella (Joannis, 1915) [Lepidoptera: Gracillariidae].

3g > Leaf-miner: Oviposition at the underside of the leaf, in the axil of a vein. The mine is a not very slender corridor. The first part is almost filled with frass; in the later part the frass lies in thick lumps. The trajectory of the mine is not angular, neither is it determined by the leaf venation. The discrimination between this mine and the one of Stigmella floslactella is difficult.

Mine of Stigmella carpinells
Mine of Stigmella carpinella on Carpinus betulus
Image: © Willem Ellis (Bladmineerders van Europa)

On Carpinus, but not yet on Ostrya, in Britain and Carpinus and Ostrya elsewhere. West Kent in Britain. Widespread in continental Europe.

Stigmella carpinella (Heinemann, 1862) [Lepidoptera: Nepticulidae].

3h > Leaf-miner: The early gallery is filled with frass, later leaving clear margins. Like Stigmella microtheriella the larva feeds on hazel or hornbeam, and its mines are often found alongside that species in the same leaf. However the mines of S. floslactella are generally wider, less angular and contain more scattered frass than those of S. microtheriella. Oviposition at the underside of the leaf, in a vein axil. Mine a slender, gradually widening corridor; the last section is clearly wider than the larva. In the first section the vaguely delimited frass line almost fills the corridor. Later the frass lies in irregular arcs and clouds, filling about one third of the width of the corridor. The trajectory of the mine is not angular, independent of the leaf venation. Pupation external, exit slit in the upper epidermis.

On Betula, Carpinus and Corylus, but not yet on Ostrya, in Britain and Carpinus, Corylus and Ostrya elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Stigmella floslactella (Haworth, 1828) [Lepidoptera: Nepticulidae].

3i > Leaf-miner: A narrow gallery, tending to follow veins of leaf. The early part with linear frass. Oviposition at the underside of the leaf, mostly close to a vein. The mine is a long, very slender corridor; even towards the end hardly wider than necessary to accomodate the growing larva. Frass in a narrow central line. The shape of the mine differs somewhat between the hostplants. In Carpinus the mine closely follows a heavy vein over a long distance; also the mine tends to be somewhat shorter and broader, and the frass often lies in a more diffuse line. The mines in Corylus are not so strictly defined by the venation and the frass line is narrower (Emmet, 1983a; Johansson ao, 1990a). Sometimes it is difficult to separate the mines from those of S. floslactella; an additional difference then is that even in the very first part of the corridor the frass of microtheriella lies in a narrow line, while the frass of floslactella seems to fill the entire corridor there. The pale golden larva lies venter-upwards in the mine. Sometimes there can be several larvae mining the same leaf.

On Carpinus betulus, Corylus avellana, Nothofagus and Ostrya carpinifolia in Britain and Carpinus spp. and Ostrya spp. elsewhere. Widespread in Britain, Ireland and continental Europe.

Stigmella microtheriella (Stainton, 1854) [Lepidoptera: Nepticulidae].



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