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Key for the identification of the mines of British Diptera recorded on
Tussilago
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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
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An upper surface corridor mine, becoming strongly broadened and
blotch-like. The mine can occupy a considerable part of a small
leaf. Mines frequently merge, and then accommodate several larvae.
Pupation external, in soil. Puparium yellow
On
Petasites, Tussilago and possibly Senecio in Britain
and elsewhere and in addition Arctium, Homogyne and possibly
Senecio elsewhere. Throughout the British Isles. Also recorded
in the Republic of Ireland and Widespread in continental Europe.
Acidia
cognata (Wiedemann, 1817) [Diptera: Tephritidae].
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Corridor mine following the mid-rib, with lateral offshoots.
Puparium yellow
On
numerous genera of Asteraceae. Throughout the British Isles, more
common in the south than the north. Also continental Europe.
Trypeta
zoe Meigen, 1826 [Diptera: Tephritidae].
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A long linear greenish-white mine which can conspicuously widen
at end, with frass in separate grains. Puparium black
On
Petasites and Tussilago in Britain and in addition
Adenostyles elsewhere. Widespread in Britain and continental
Europe, Also recorded in Alaska and Canada.
Phytomyza
tussilaginis Hendel, 1925 [Diptera: Agromyzidae].
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Key
for the identification of the mines of British
non-Diptera recorded on Tussilago
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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: 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).
Recorded
on numerous genera and species of several plant families, including
Tussilago, in Britain and elsewhere. Widespread in Britain
and continental Europe. Also recorded from the Channel Is.
Cnephasia
incertana (Treitschke, 1835) [Lepidoptera: Tortricidae]
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1b >
The mine is brownish and extends along the midrib, sometimes
branching (British
leafminers).
Oviposition
on top of the midrib. Immediately after emergence the larva gnaws
a cavity in the midrib, and from there an irregular blotch is made
adjacent to the midrib. The larva continues living in the midrib
that is gradully hollowed out, making from there broad, brownish,
full depth excursions in the blade. The mine contains much frass;
most of it is concentrated in the area immediately bordering the
midrib. Older, no longer occupied parts of the mine often split
open. Mines mainly on the lower leaves. The slender larvae move
surprisingly fast upon disturbance; when they rest (in daytime)
they lie lengthwise in the hollowed midrib. Pupation outside the
mine (Bladmineerders
van Europa).
Recorded
on Artemisia, Carduus, Cirsium and possibly Tussilago
in Britain and Carduus and Cirsium elsewhere. Widespread
in Britain and continental Europe.
Scrobipalpa
acuminatella (Sircom, 1850) [Lepidoptera: Incurvariidae]
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| 1c > The
larva mines the leaves creating an irregular blotch (UKMoths).
Initially a branching corridor, later more an elongate upper-surface
blotch from the leaf base to the leaf margin, finally occupying
a good part of the leaf. Most frass is deposited in one section
of the mine, forming a crust below which the very agile larvae can
retreat (Bladmineerders
van Europa). |
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Mine of Scrobipalpula tussilaginis on Tussilago
Axmouth Undercliff, Devon
Image: Bob Heckford |
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Recorded
on Tussilago in Britain and on Petasites and Tussilago
elsewhere. A scarce and very local species, only discovered in
Britain in 1983 where it was found on the coast in south Devon.
It is now known to occur in a few localities eastwards to Hants
on sparsely vegetated coastline. Widespread in continental Europe.
Scrobipalpula
tussilaginis (Stainton, 1867)
[Lepidoptera: Gelechiidae]
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