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CERASTIUM. Mouse-ears. [Caryophyllaceae] |
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Fourteen species of Cerastium are recorded in Britain. These include the native Alpine Mouse-ear (C. alpinum), Arctic Mouse-ear (C. arcticum), Common Mouse-ear (C. fontanum), Dwarf Mouse-ear (C. pumilum), Field Mouse-ear (C. arvense), Little Mouse-ear (C. semidecandrum), Sea Mouse-ear (C. diffusum), Starwort Mouse-ear (C. cerastoides) and Sticky Mouse-ear (C. glomeratum). Three Diptera miners, the anthomyiids Pegomya flavifrons and Delia echinata and the drosophilid Scaptomyza graminum, are recorded on Cerastium in Britain. The latter is also doubtfully recorded on Myosoton in Britain. The anthomyiid Pegomya holosteae is recorded on Cerastium by Ackland in Chandler (1978), but it is not clear whether the host association is British or Foreign. Although the anthomyiid Delia florilega has been recorded on Cerastium in Britain and elsewhere, it is primarily a stem/petiole borer. Elsewhere the agromyzids Amauromyza flavifrons, Chromatomyia horticola and Ophiomyia melandricaulis, and the anthomyiids Delia coronariae, Delia echinata, Pegomya flavifrons and Pegomya holosteae and the drosophilid Scaptomyza graminum are recorded on Cerastium. Seven non-Diptera leaf-miners are recorded on Cerastium in Britain (see below). Elsewhere eight British non-Diptera miner is recorded on Cerastium (see below). The coleophorid Coleophora striatipennella is recorded as a seed-feeder on Cerastium in Britain and elsewhere. A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Cerastium is provided in Bladmineerders van Europa. This includes Amauromyza flavifrons, Chromatomyia horticola, Delia coronariae, Delia echinata, Delia florilega, Ophiomyia melandricaulis, Pegomya flavifrons, Pegomya holosteae, Scaptomyza graminum, Apterona helicoidella, Caryocolum petrophila, Caryocolum alsinella, Caryocolum junctella, Caryocolum proxima, Cnephasia incertana, Cnephasia asseclana, Cnephasia stephensiana, Coleophora chalcogrammella, Coleophora lithargyrinella, Coleophora nubivagella, Coleophora solitariella, Orthochaetes insignis, Scythris siccella but not Caryocolum vicinella and Coleophora rectilineella. |
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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). 1a > Leaf-miner: 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) (Bladmineerders van Europa).
Delia echinata (Seguy, 1923) [Diptera: Anthomyiidae]. 1b > Leaf-miner 2a > 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.
Pegomya flavifrons (Walker, 1849) [Diptera: Anthomyiidae]. 2b > 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.
Pegomya holosteae (Hering, 1924) [Diptera: Anthomyiidae]. 2c > Leaf-miner: A long, narrow, winding corridor running towards the midrib, widening to a blotch. 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 (Fallén, 1823) [Diptera: Drosophilidae]. |
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Key for the identification of British non-Diptera mines recorded on
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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 at least 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).
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1a > Leaf-miner and case bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tisses via a hole cut in the epidermis. Mine does not contain frass (Coleophora species) 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 e.g. Incurvaria species. |
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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° (Bladmineerders van Europa).
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Coleophora chalcogramella Zeller, 1839 [Lepidoptera: Coleophoridae].
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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 (British leafminers). The larval case is very distinctive when fully grown as it is a pale pink colour and has a double dorsal keel (UKMoths). 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 (Bladmineerders van Europa).
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Coleophora lithargyrinella Zeller, 1849 [Lepidoptera: Coleophoridae].
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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 (British leafminers). 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 (Bladmineerders van Europa).
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Coleophora solitariella Zeller, 1849 [Lepidoptera: Coleophoridae].
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3a > Leaf-miner: Initially mining the leaves, but later on spun flowers and seeds (UKMoths).
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Caryocolum alsinella (Zeller, 1868) [Lepidoptera: Gelechiidae].
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3b > 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 (Bladmineerders van Europa).
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Caryocolum junctella (Douglas, 1851) [Lepidoptera: Gelechiidae].
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3c > Leaf-miner: In Belgium the larva lives in a silken tube in the sand and feeds on the leaves of Cerastium fontanum touching the ground. Pupation in a cocoon in the sand (Belgian Lepidoptera).
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Caryocolum marmoreum (Haworth, 1828) [Lepidoptera: Gelechiidae].
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3d > 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).
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Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae].
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3e > Leaf-miner: Rather narrow corridor, untidy and sometimes branched, starting from the base of the leaf, in particular the midrib. Sides of the corridor irregularly eaten out, not really parallel. Frass mostly present, and then in a central line. The legless larva is capable of leaving the mine and start a new one elsewhere. These later mines are much broader, and the frass is scattered irregularly. (Bladmineerders van Europa.
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Orthochaetes insignis (Aube, 1863) [Coleoptera: Curculionidae].
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| Last updated 04-Feb-2012 Brian Pitkin |  |
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