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(Coleoptera, Diptera, Hymenoptera and Lepidoptera)
by
Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds
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AMARANTHUS.
Pigweeds. [Amaranthaceae]
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About thirty-three
species of Amaranthus are recorded in Britain, all of them
introduced. They include White Pigweed (A. albus), Prostrate
Pigweed (A. blitoides), Guernsey Pigweed (A. blitum),
Indehiscent Amaranth (A. bouchonii), Cape Pigweed (A.
capensis), Love-lies-bleeding (A. caudatus), Purple Amaranth
(A. cruentus), Perennial Pigweed (A. deflexus), Short-petalled
Pigweed (A. graecizans), Green Amaranth (A. hybridus),
Prince's-feather (A. hypochondriacus), Dioecious Amaranth
(A. palmeri), Powell's Amaranth (A. powellii), Mucronate
Amaranth (A. quitensis), Common Amaranth (A. retroflexus), Indehiscent Pigweed (A. standleyanus) and Thunberg's
Pigweed (A. thunbergii). The BSBI provide a downloadable plant crib for Amaranthus.
Eight British miners are recorded on Amararnthus.
A key to the European miners recorded on
Amaranthus is provided in Bladmineerders van Europa.
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Key for the identification of the known mines of British
Diptera recorded on Amaranthus
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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).
See Key to non-Diptera.
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1a > 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). |
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On
? Agrostemma, ? Arenaria, Cerastium, ? Dianthus, ? Gypsophila, ? Lychnis,
? Saponaria, Silene, ? Spergularia, ? Stellaria and Vaccaria [Caryophyllaceae], Atriplex, ? Chenopodium, Spinacia [Chenopodiaceae], Phlox [Polemoniaceae], but not yet on Amaranthus, in Britain.
Also recorded on other hosts elsewhere. Known only from Warwick
and West Ross in Britain, Europe, Japan, Canada and Alaska.
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Delia echinata (Seguy, 1923) [Diptera: Anthomyiidae]. |
1b > Leaf-miner: Oviposition can take place in the leaf, where a short
mine is formed. The young larva feeds towards the mid-rib and down
into the stem. Alternatively a true mine can be formed in the stem
before the larva burrows deeper into the pith. Pupation external.
Puparium yellow |
On Chenopodium, but not yet on Amaranthus, in Britain and Amaranthus and Chenopodium elsewhere. Recorded in Cambridge (Cambridge) and Derby (Worthington).
Widespread in continental Europe.
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Amauromyza
chenopodivora Spencer, 1971 [Diptera: Agromyzidae]. |
1c > 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). |

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.
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Scaptomyza
graminum (Fallén, 1823) [Diptera: Drosophilidae]. |
1d > 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. |
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Polyphagous. On 119 plant genera in 31 plant families of which only 4 plant genera in 2 plant families, but not yet on Amaranthus, in Britain. Local, probably introduced
to Britain. Widespread in continental Europe particularly in Botanical
Gardens and glasshouses. Also recorded in Egypt.
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Liriomyza bryoniae (Kaltenbach, 1858) [Diptera: Agromyzidae]. |
1e > 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. |
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On
more than 40 host genera in 15, but not yet on Amaranthus, families in Britain. Widespread
throughout Britain. Also recorded in the Republic of Ireland.
Widespread in continental Europe.
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Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae]. |
1f > Leaf-miner: Mine linear, whitish, both upper and lower surface. Pupation internal,
at the end of the mine with the anterior spiracles projecting through
the epidermis (Spencer, 1976:
433). Upper-surface,
less often lower-surface corridor. Frass in isolated grains. Pupation
within the mine, in a, usually lower-surface, pupal chamber. A long whitish upper surface corridor, which eventually goes lower surface. |
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Two
highly polyphagous species of Chromatomyia, with indistinguishable
mines, have been recorded in Britain. These are syngenesiae (Hardy) and horticola (Goureau) which can only be distinguished by the male genitalia. Both species are widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae. Records on Asteraceae not based on examination of male genitalia are treated in this account as Chromatomyia 'atricornis'.
Chromatomyia
horticola has been recorded on Cosmos elsewhere, but not yet on Cotinus, in Britain.
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Chromatomyia
horticola (Goureau, 1851) [Diptera: Agromyzidae]. |
Key for the identification of the known mines of British
non-Diptera recorded on Amaranthus
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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 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: The red and white
larvae feed by mining the leaves forming a contorted gallery.
A
strongly contorted, often intestinine-like corridor, often forming
a secondary blotch. Much green frass in broad arcs. Full grown larva
mostly on top of the midrib. Pupation external. |
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Chrysoesthia drurella larva, dorsal
Image: © Willem Ellis (Bladmineerders van Europa) |
On Atriplex and Chenopodium, but not yet on Amaranthus,
in Britain plus Amaranthus and Monolepis elsewhere.
Widespread in Britain and continental Europe.
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Chrysoesthia
drurella (Fabricius, 1775) [Lepidoptera: Gelechiidae]. |
1b > Leaf-miner: Whitish blotches in the leaves.
The
mine begins as a short zigzagging corridor, that very soon becomes
overrun by a large, perfectly transparent blotch. Frass in a big
black central lump. In fresh mines something like primary feeding
lines are recognisable, normally seen only in Diptera mines. Pupation
external, exit a rather untidy hole. A
large, whitish blotch sometimes occupying most or all of the leaf.
The frass is mostly ejected from the mine.. |
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On Atriplex and Chenopodium, but not yet on Amaranthus, in Britain plus Amaranthus, Bassia and Spinacia elsewhere. Widespread in Britain
and continental Europe.
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Chrysoesthia
sexguttella (Thunberg, 1794) [Lepidoptera: Gelechiidae]. |
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