The leaf and stem mines of British flies and other insects
 

(Coleoptera, Diptera, Hymenoptera and Lepidoptera)

by Brian Pitkin, Willem Ellis, Colin Plant and Rob Edmunds

N.B. Links to the latest version of 'Leafminers and plant galls of Europe' are being edited

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SERRATULA. Saw-wort. [Asteraceae]


Only one species of Serratula is recorded in Britain - the native Saw-wort (S. tinctoria).

Nine or ten British miners are recorded on Serratula.

Saw-wort - Serratula tinctoria. Image: © Linda Pitkin
Saw-wort
Serratula tinctoria



Key for the identification of the known mines of British
Diptera recorded on Serratula


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.


1a > 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 (Bladmineerders van Europa). A long whitish upper surface corridor, which eventually goes lower surface (British leafminers).

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'.

Chromatomiya 'atricornis' is tentatively recorded on Serratula elsewhere but not on yet Serratula in Britain.

Chromatomyia syngenesiae is recorded on Achillea in Britain.

Chromatomyia horticola (Goureau, 1851) [Diptera: Agromyzidae]
OR
Chromatomyia syngenesiae Hardy, 1849 [Diptera: Agromyzidae].

1b > Leaf-miner: A shallow, upper surface, whitish linear mine. Pupation external (Spencer, 1972b: 72 (fig. 233A), 77).

Tortuous, upper-surface corridor, often somewhat geryish, and/or following the leaf margin. Frass grains fairly small, separated by about their own diameter. Primary feeding lines often conspicuous. Pupation outside the mine; exit slit in upper epidermis (Bladmineerders van Europa).

A long whitish upper surface mine. The frass grains are small and can occur close together (British leafminers).

Mine of Phytomyza cirsii on Cirsium arvense. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mine of Phytomyza cirsii on Cirsium arvense
Image: © Willem Ellis (Bladmineerders van Europa)
Phytomyza cirsii larva,  lateral
Phytomyza cirsii larva, lateral
Image: © Willem Ellis (Bladmineerders van Europa)

On Cirsium, but not yet on Serratula, in Britain, plus Carduus, Cyanara, ? Scolymus and Serratula elsewhere. Widespread in Britain, probably not uncommon but overlooked. Also recorded from the Republic of Ireland. Widespread and common in much of Europe

Phytomyza cirsii Hendel, 1923 [Diptera: Agromyzidae].

1c > Leaf-miner: Long narrow interparenchymal mine, greenish. Pupation in leaf at end of mine (Spencer, 1976: 503 (fig. 880)).

Unusually long, interparenchymatous, therefore yellowish corridor that remains of equal width throughout its length. (In some plants with thin leaves, like Cirsium oleraceum the mines are not interparechymatous but either full-depth or alternating upper- and lower-surface). The mine makes few curves, and hardly any u-turn, causing the mine to usually occupy the entire length of a leaf. Frass in two rows of grains along the sides. Pupation within the mine, in a lower-surface pupariuml chamber; the anterior spiracles penetrate the epidermis (Bladmineerders van Europa).

Mines of Phytomyza spinaciae on Cirsium arvense. Image: © Willem Ellis (Source: Bladmineerders en plantengallen van Europa)
Mines of Phytomyza spinaciae on Cirsium arvense
Image: © Willem Ellis (Bladmineerders van Europa

On Carduus, Centaurea, Cirsium and Onopordum, but not yet on Serratula, in Britain and in addition Cnicus and Serratula elsewhere. Only recorded from Warwick and Stafford in Britain. Also recorded in the Repupublic of Ireland. Widespread in continental Europe, range extending to the Kirghiz Republic of the [former] U.S.S.R.

Phytomyza spinaciae Hendel, 1928 [Diptera: Agromyzidae].



Key for the identification of the known mines of British
non-Diptera recorded on Serratula


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).


1a > Leaf-miner and case-bearer: The larva lives outside the mine, protected by a case, and feeds on the underlying plant tissues via a hole cut in the epidermis. From that point it eats away as much leaf tissue as it can reach without fully entering the mine. Mine does not contain frass (Coleophora species)

2

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.

3

2a > Leaf-miner and case-bearer: Larva mines leaves (British leafminers). The larva builds a case from silk, resembling a razor shell in appearance. (UKMoths). The full-grown case is 12 mm long and blackish-brown (British leafminers). The full grown larva lives in a blackish brown trivalved tubular silken case of about 8 mm.

On Arctium, Centaurea, Cirsium, Serratula in Britain and Arctium, Carduus, Centaurea, Cirsium, Saussurea and Serratula elsewhere. Widespread in Britain, Ireland and continental Europe.

Coleophora paripennella Zeller, 1839 [Lepidoptera: Coleophoridae].

3a > Leaf-miner: Short, gradually widening, brown, corridor, 9-13 mm long and 0.5-2 mm wide. At he start of the mine a small lower-surface hole, lined with silk, through which frass is ejected. The older larva lives free in a spinning under the leaf or, even later, in a leaf that is spun upwards into a pod (Bladmineerders van Europa).

On Serratula in Britain and elsewhere. Britain (Karsholt and van Nieukerken in Fauna Europaea) including East Cornwall and West Cornwall. Russia East and East Palaearctic.

Agonopterix kuznetzovi Lvovsky, 1983 [Lepidoptera: Depressariidae].

3b > Leaf-miner: The eggs of this species are laid on a leaf, with the larvae mining the underside of the leaf, until a late instar when it feeds in a web under the midrib of the leaf, causing visible blotching on the upperside (UKMoths). Short, full depth corridor. The larva relatively long lives as a miner, but finally leaves the mine and continues living in spinning along the midrib at the leaf underside, from where windows are eaten in the leaf (Bladmineerders van Europa).

Agonopterix propinquella on Cirsium arvense
Mines of Agonopterix propinquella on Cirsium arvense
Image: © Ian Smith (UKMoths)

On Cirsium, but not yet on Serratula, in Britain and Arctium, Carduus, Centaurea, Cirsium, Cynara, Mycelis and Serratula elsewhere. Widespread in Britain and continental Europe.

Agonopterix propinquella (Treitschke, 1835) [Lepidoptera: Depressariidae].

3c > 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).

Polyphagous. On numerous genera and species of several plant families, but not yet on Serratula, in Britain. On numerous genera and species of several plant families, including Serratula, elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

Cnephasia incertana (Treitschke, 1835) [Lepidoptera: Tortricidae].

3d > Long corridor, often following the leaf margin, with little frass and with the sides irrregularly eaten out. The first part of the corridor is full depth and makes a few close loops; the later part is more upper-surface and rather wide. Primary feeding lines often conspicuous. No morphological differences are known between the larva of S. rubidum and S. testaceum (Steinhausen, 1994a). However, there is a phenological difference: the larva of testaceum hibernates in the mine and continues feeding after winter; S. rubidum vacates the mine before winter and pupates in the soil. Hering (1957a) suggests that the identification of the beetles is an easy matter, but that is contradicted by Warchalowski (2003a). (Bladmineerders van Europa)

On Carduus, Centaurea and Cirsium, but not yet on Serratula, in Britain and on Arctium, Carduus, Cirsium, Centaurea, Cynara, Onopordum and Serratula elsewhere. Widespread in Britain and continental Europe.

Sphaeroderma testaceum (Fabricius, 1775) [Coloeptera : Chrysomelidae]

3e> Long corridor mine, without obvious relation with the leaf margin, with little frass and irregularly eaten out sides. The first part of the mine is full depth and makes a few close loops; the second part is upper-surface and considerably wider. Primary feedings lines often obvious. The larva is so broad that is completely fills the mine. No morphological differences are known between the larvae of S. rubidum and those of S. testaceum (Steinhausen, 1994a). The larva leaves the mine to pupate in the soil (the larva of testaceum hibernates in the mine.) Hering (1957a) suggests that the imagines are easily separated, but this is contradicted by Warchalowski (2003a). (Bladmineerders van Europa)

On Arctium, Carduus, Carthamus, Centaurea, Cirsium, Corylus, Cynara, Onopordum and Serratula in Britain and on Arctium, Carduus, Centaurea, Cynara and Serratula elsewhere. Widespread in Britain and continental Europe.

Sphaeroderma rubidum (Graells, 1858) [Coloeptera : Chrysomelidae]



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