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PENTAGLOTTIS. Green Alkanet. [Boraginaceae] |
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Only one species of Pentaglottis, Green Alkanet (P. sempervirens), is recorded in Britain. It is introduced. Two Diptera miners, the agromyzids Agromyza abiens and Agromyza myosotidis, are recorded on Pentaglottis in Britain. These also occur on Symphytum in Britain. A key to the miners on both host plant genera is provided. Elsewhere the agromyzids Agromyza abiens and Agromyza myosotidis are recorded mining Pentaglottis. One non-Diptera leaf-miner is recorded on Pentaglottis in Britain and elsewhere (see below). |
 Green Alkanet Pentaglottis sempervirens |
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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: A large blotch mine, several larvae feeding together.
Agromyza ferruginosa Wulp, 1871 [Diptera: Agromyzidae]. 1b > Leaf-miner: A large, irregular blotch mine with a short linear section in the first instar which is frequently entirely enveloped in the fully developed mine and may then be no longer visible. Puparium reddish brown
Agromyza myosotidis Kaltenbach, 1864 [Diptera: Agromyzidae]. 1c > Leaf-miner: A narrow linear leaf mine, which developes into a large blotch. Several larvae frequently feed together and the resulting mine can entirely fill the leaf. Puparium reddish brown
Agromyza abiens Zetterstedt, 1848 [Diptera: Agromyzidae]. 1d > Leaf-miner: Mine initially linear, later developing into a whitish blotch, becoming blackish. Pupation in mine on lower surface. Puparium normally dark reddish brown
Phytomyza medicaginis Hering, 1925 [Diptera: Agromyzidae]. |
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Key for the identification of the mines of British
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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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1 > Leaf-miner and case-bearer: The larva feeds in a distinctive case made from hairy leaf fragments of the foodplant (UKMoths). The young larva feeds on the developing seeds and hibernates in its first case which is made of the tip of a petal. After hibernation it makes a hoary, laterally flattened composite leaf case (resembling a willow catkin). Full depth mines are made at the margin of the leaves, that thereby look peculiarly damaged. Mouth angle 70° (Bladmineerders van Europa). Initially forms a blotch mine, in the centre of a leaf, which it excises for its initial case. In the spring it repeatedly extends its case and it resembles a jagged catkin of willow. The larva may wander from its foodplant and attach to other plants or fences etc (British leafminers).
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| Last updated 07-Feb-2012 Brian Pitkin |  |
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