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

 

STELLARIA. Chickweeds and Stitchworts. [Caryophyllaceae]

 

Eight species of Stellaria are recorded in Britain. These include the native Lesser Stitchwort (S. graminea), Greater Stitchwort (S. holostea), Common Chickweed (S. media), Greater Chickweed (S. neglecta), Wood Stitchwort (S. nemorum), Lesser Chickweed (S. pallida), Marsh Stitchwort (S. palustris) and Bog Stitchwort (S. uliginosa). The BSBI provide a downloadable plant crib for Stellaria nemorum vs Myosoton aquaticum.

Stellaria uliginosa is treated as Stellaria alsine by Stace (2010).

Eighteen British miners are recorded on Stellaria.

The coleophorid Coleophora striatipennella is recorded as a seed-feeder on Stellaria in Britain and elsewhere.

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

Betony - Stachys officinalis. Image: © Brian Pitkin
Stitchwort
Stellaria holostaea


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


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 > Stem miner: A shallow external stem-mine (Spencer, 1972b: 29).

The mine generally starts as a fine, lower-surface, corridor the seems to end upon a thick vein. In reality the corridor continues by way of the petiole to the stem, where a very long mine is formed in the rind. Frass in widely spaced grains. Pupation within the mine, mostly just above a node; the anterior spiracles penetrate the epidermis.

On Lychnis, Moehringia and Silene, but not yet on Stellaria, in Britain and additional genera and species of Caryophyllaceae elsewhere. Only known from Hunts, Monmouth and Warwick in Britain. Widespread in continental Europe.

Ophiomyia melandricaulis Hering, 1943 [Diptera: Agromyzidae].

1b > Leaf and stem miner: Eggs are scattered individually over the leaf upper surface; they are only loosely attached to the plant. The egg shell has a honeycomb structure. The larva begins with first mining one of the top leaves completely out. Next the larva moves down to another leaf, by way of a tunnel made in the stem. In this way several leaves are mined out, completely and full depth. In the attacked part of the plant the stem has become translucent; the damage causes the plant tip to wilt. In the first mines almost no frass is to be found, further down it is deposited in coarse grains. Pupation generally outside the mine (Miles, 1953).

On ? Agrostemma, ? Arenaria, Cerastium, ? Dianthus, ? Gypsophila, ? Lychnis, ? Saponaria, Silene, ? Spergularia, ? Stellaria and Vaccaria [Caryophyllaceae], Atriplex, ? Chenopodium, Spinacia [Chenopodiaceae], Phlox [Polemoniaceae] in Britain. Also recorded on other hosts elsewhere. Known only from Warwick and West Ross in Britain, Europe, Japan, Canada and Alaska.

Delia echinata (Seguy, 1923) [Diptera: Anthomyiidae].

1c > 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.

A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings.

Polyphagous. On more than 40 host genera in 15 families, but not yet on Stellaria, in Britain,. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

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

1d > Leaf-miner: Narrow corridor, leading to a large blotch. The blotch has lower- and upper-surface parts, and is full depth where these overlap. Pupation external (Robbins, 1991a).

On ? Brassica, ? Sisymbrium, Stellaria and Potamogeton in Britain and ? Stellaria elsewhere. Widespread from Caithness in the north to Kent in the south-east of Britain. Widespread in continental Europe.

Scaptomyza griseola (Zetterstedt, 1847) [Diptera: Drosophilidae].

1e > Leaf-miner: Mine a very long and straight corridor, only after a change of leaf, blotch-like. Corridor first following leaf margin, turning round at the apex, then blotch like and running towards the leaf base. Frass often indistinctly delimited and faded, blackish green.

On Cerastium and Stellaria in Britain and Cerastium, Moehrongia and Stellaria elsewhere (records ambiguous). Only recorded from Wilts in Britain. Widespread in continental Europe.

Pegomya holosteae (Hering, 1924) [Diptera: Anthomyiidae].

1f > Leaf-miner: Upper side blotch mine beginning with a deeper, almost full depth corridor. Frass grains not in thread-like pieces, irregularly scattered. In the large, later blotch indistinct primary and secondary frass lines are found; the frass accumulated in the middle.

Each mine begins with one, rarely two, oval egg shells attached to the leaf underside. Sometimes a number of of young mines, and eggs, on one leaf. The first part of the mine is a tortuous corridor, quickly turning into a large blotch. Most of the blotch is full depth, only some patches are upper-surface, and greenish in transparency. According to the literature copious frass in present in dispersed lumps. In my experience the larva -that then looks very dark- may accumulate all frass in its body. The larva is capable of leaving its mine, and starting a new one elsewhere. These secondary mines can be recognised by the large hole that was made by the larva when entering. Pupation outside the mine.

A gallery then a blotch, larger and deeper than Amauromyza flavifrons. In large leaves the mine is upper surface and all in one piece. In small leaves the whole leaf may be covered by a full depth mine with the larva mining several leaves in British leafminers.

On Cerastium, Lychnis, Myosoton, Silene and Stellaria in Britain and elsewhere. Widespread in Britain and continental Europe.

Pegomya flavifrons (Walker, 1849) [Diptera: Anthomyiidae].

1g > Leaf-miner: The mine starts as a long, narrow, winding corridor running towards the midrib, widening to a blotch. Usually upper-surface, but in small leaves also full-depth parts may occur. The blotch has broad lobes; in their ends most frass is accumulated in the form of green patches or clouds. Sometimes several larvae share mine. Pupation usually in the soil, less often in the leaf (and then generally not in the mine itself but in a small separated mine, that may even be made in the petiole).

Scaptomyza graminum on
Mine of Scaptomyza graminum on Cerastium glomeratum
Image: © Jean-Yves Baugnée (Bladmineerders van Europaa)

On ? Amaranthus, Cerastium, Lychnis, Myosoton, Nasturtium, Silene, Stellaria, Atriplex, ? Anthyllis, ? Lupinus, ? Medicago, ? Montia and ? Antirrhinum in Britain.

On Amaranthus, Lepidium, Moricandia, ? Rorippa, Agrostemma, Arenaria, Cerastium, Corrigiola, Cucubalus, Dianthus, Gypsophila, Lychnis, Moehringia, Myosoton, Polycarpon, Saponaria, Silene, Spergularia, Stellaria, Vaccaria, Viscaria, Atriplex, Beta, Chenopodium, Obione, Salicornia, Spinacia, Anthyllis, Lupinus, Medicago, Allium, Montia, Portulaca and Antirrhinum elsewhere. Widespread in Britain and continental Europe.

Scaptomyza graminum (Fallén, 1823) [Diptera: Drosophilidae].

1h > Leaf-miner: A white linear-blotch mine, the linear section sometimes not detectable as it becomes enveloped in later blotch (Spencer, 1976: 162-3, figs 296-7).

Upper-surface, less often lower-surface, corridor, followed, and often overrun, by a large blotch. Even when the corridor is overun, it usually remains recognisable in the frass pattern. The mine looks whitish in the field. The blotch does not contain much frass, in the form of small black grains, dispersed and stuck to the floor of the mine. Feeding punctures upper-surface (always?). Pupation outside the mine.

A common miner, forming a white linear blotch mine (the blotch may obscure the linear portion of the mine) in both native and garden plants.The mine is also illustrated in the Encyclopedia of Life.

Polyphagous. On Agrostemma, Dianthus, Lychnis, Saponaria, Silene, Stellaria [Caryophyllaceae] and Atriplex, Beta and Spinacia [Chenopodiaceae] in Britain. Widespread in Britain and continental Europe. Also Canada.

Amauromyza flavifrons (Meigen, 1830) [Diptera: Agromyzidae].

1i > Leaf-miner: A short, irregular, linear upper surface mine on any part of the leaf. Also recorded from young pods (Bland, 1997a).

Long corridor mine. As a rule the first part of the mine is lower-surface, the later part upper-surface. Often the loops are so dense that a secondary blotch is the result. Because upper- and lower-surface corridor segments often cross, the mine obtains a strange array of transparant patches. There is no association with the midrib. Frass in strings and thread fragments. Pupation outside the mine; exit slit in upper epidermis.

Mine not associated with the veins or midrib of the leaf (It is this character which enables distinction from another Agromyzid pest species - Liriomyza huidobriensis). The larvae may leave one leaf (if not large enough) and enter another leaf, via the petiole). It exits the leaf to pupate through a semi-circular slit in the upper surface of the leaf.

Polyphagous. On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Stellaria in Britain. Local, probably introduced to Britain. Widespread in continental Europe particularly in Botanical Gardens and glasshouses. Also recorded in Egypt.

Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae].

1j > 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).

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 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].

1k > Leaf-miner: Mine only in the leaf lamina (not the mid-rib). Mine not simultaneously blotch-like (on the upper side or under side) and with very fine frass grains. Mine not touching the midrib. Mine at least in places greenish in transmitted light when seen from either the dorsal side or ventral side. Frass plentiful, irregularly scattered throughout the mine. Pupation always external. The egg shell lies on the leaf surface at the beginning of the mine.

On Lychnis flos-cuculi, but not yet on Stellaria, in Britain and elsewhere. Recorded in Britain by Ackland (1978). Widespread in continental Europe. Also recorded in the East Palaearctic and Nearctic Regions.

Delia coronariae (Hendel, 1925) [Diptera: Anthomyiidae].



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


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 young larva lives mainly inside the mine. Mine usually contains frass. In later instars the larva may live between spun, shoots, flowers or seeds (Caryocolum species)

3

2a > Leaf-miner and case-bearer: In autumn the larva makes a short corridor, that widens into a small blotch, out of which the first case is cut. The final case, after hibernation, is a brown, tubular silken case, three-valved, c. 6 cm long, with a mouth angle of about 30°.

On Cerastium and Stellaria in Britain and Arenaria, Cerastium, Moehringia and Stellaria elsewhere. Distribution in Britain unknown. Widespread in continental Europe.

Coleophora chalcogrammella Zeller, 1839 [Lepidoptera: Coleophoridae].

2b > Leaf-miner and case-bearer: Larva mines leaves of Caryophyllaceae. The final case is tubular, 8 mm long, with a dorsal keel which forks and continues as two ridges to the anal end of the case. The larval case is very distinctive when fully grown as it is a pale pink colour and has a double dorsal keel. Larva in a trivalved tubular silken case of 8 mm long, with a mouth angle of 25°-30°. The case is pale brown. A unique detail is the presence of a double dorsal keel, but this only occurs when the larva is fully developed: the foremost part of the keel remains single, but already the fork appears before the middle.

Case and mine of Coleophora lithargyrinella on Stellaria holostea Image: © Rob Edmunds (British leafminers)
Case and mine of Coleophora lithargyrinella on Stellaria holostea
Image: © Rob Edmunds (British leafminers)

On Arenaria, Cerastium, Silene and Stellaria in Britain and Arenaria, Cerastium and Stellaria elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Coleophora lithargyrinella Zeller, 1849 [Lepidoptera: Coleophoridae].

2c > Leaf-miner and case-bearer: Larva mines leaves, forming a case from an excised mine. This case is later extended, and widened by slitting the ventral side to insert a gusset. The full-grown case is 8 mm long with a single ventral keel. Full grown larva in a slender greyish white three-valved tubular silken case of c. 8 mm; mouth angle about 45°. Often several cases together on a small number of plants.

On Cerastium, Myosoton, Silene and Stellaria in Britain and Arenaria, Cerastium, Myosoton and Stellaria elsewhere. The Isle of Wight in Britain. Widespread in continental Europe.

Coleophora solitariella Zeller, 1849 [Lepidoptera: Coleophoridae].

3a > Leaf-miner: Initially mining the leaves, but later on spun flowers and seeds.

On Cerastium and Minuartia, but not yet on Stellaria, in Britain and Arenaria, Cerastium, Minuartia, Moehringia and Stellaria elsewhere.

Caryocolum alsinella (Zeller, 1868) [Lepidoptera: Gelechiidae].

 

3b > Leaf-miner: The larva feeds at first in a mine, then in spun shoots or seed capsules. Long narrow gallery close to the midrib. Older larvae live free among spun leaves or inflorescence.

On Stellaria in Britain and elsewhere. Locally distributed in England and Wales. Widespread in continental Europe.

Caryocolum blandella (Douglas, 1852) [Lepidoptera: Gelechiidae].

3c > Leaf-miner: Young larvae make mines, but the mines have not been described. Older larvae live among the tips of the shoots, that are spun together.

On Cerastium and Stellaria in Britain and elsewhere. East Sutherland and South Essex in Britain. Widespread in continental Europe.

Caryocolum junctella (Douglas, 1851) [Lepidoptera: Gelechiidae].

3d > Leaf-miner: Gallery-like full depth mine, mainly in the base of the leaf, with irregularly scalloped sides. Frass in the oldest part of the mine in thick black grains; further on the mine does not contain frass at all. In the transition between the two parts there is a hole in the epidermis from which frass is ejected. Older larvae live free, between spun terminal shoots.

On Stellaria in Britain and elsewhere. Britain including Berks, Hereford, Notts, Oxford, Salop, South Hants, Surrey and Northern Ireland. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Caryocolum tricolorella (Haworth, 1812) [Lepidoptera: Gelechiidae].



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