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ALOPECURUS. Foxtails. [Poaceae] |
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Thirteen species of Alopecurus are recorded in Britain. These include the native species Orange Foxtail (A. aequalis), Black-grass (A. myosuroides), Alpine Foxtail (A. borealis), Bulbous Foxtail (A. bulbosus), Marsh Foxtail (A. geniculatus) and Meadow Foxtail (A. pratensis). One miner, the agromyzid Cerodontha denticornis is recorded on Alopecurus in Britain. Miners on grasses should be reared, whenever possible, to confirm their identity. Elsewhere the grass-feeding agromyzids Agromyza mobilis, Agromyza nigrella, Agromyza nigripes, Cerodontha calamagrostidis, Cerodontha denticornis, Cerodontha flavocingulata, Cerodontha incisa, Chromatomyia fuscula, Chromatomyia nigra, Liromyza flaveola and Metopomyza flavonotata and the polyphagous ephydrid Hydrellia griseola are recorded mining Alopecurus. No non-Diptera miners are recorded on Alopecurus in Britain. Elsewhere two British non-Diptera miners, Elachista albifrontella and Elachista maculicerusella are recorded on Alopecurus (see below). The coloephorid Coleophora lixella is recorded as a seed feeder on Alopecurus in Britain. A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Alopecurus is provided in Bladmineerders van Europa. This includes Agromyza mobilis, Agromyza nigripes, Agromyza nigrella, Cerodontha denticornis, Cerodontha incisa, Chromatomyia nigra, Chromatomyia fuscula, Cerodontha calamagrostidis, Liriomyza flaveola, Cerodontha flavocingulata, Hydrellia griseola, Metopomyza flavonotata, Coleophora lixella, Elachista albifrontella and Elachista maculicerusella, but not Elachista dimicatella. |
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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). 1 > 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.
Cerodontha (Cerodontha) denticornis (Panzer, 1806) [Diptera: Agromyzidae]. |
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Key for the identification of the mines of British non-Diptera recorded on
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Note: Larvae of mining Coleoptera, Hymenoptera and Lepidoptera usually have six thoracic 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). Larva 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. 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. The mines of Elachista are insufficiently known to identify and adults should be reared.
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1a > 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).
Elachista albifrontella (Hübner, 1817) [Lepidoptera: Elachistidae]
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1b > Leaf-miner: Larva makes a large whitish blotch and mines the leaf downwards. The frass tends to be deposited in the upper part of the mine (British leafminers). Oviposition usually not far from the leaf tip. From there descends an irregular blotch mine. Hering (1957a) describes the mine as flat and quite shallow, giving it a greenish, rather than whitish appearance. Frass initially in the oldest, upper part of the mine, later in strings. The larva can leave its mine and restart elsewhere. Normally only one larva per mine, but sometimes two or even three mines in a leaf. Pupation outside the mine (Bladmineerders van Europa).
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Elachista maculicerusella (Bruand, 1859) [Lepidoptera: Elachistidae] |
| Last updated 04-Feb-2012 Brian Pitkin |  |
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