CAPSELLA. Shepherd's-purses. [Brassicaceae]

Two species of Capsella are recorded in Britain. These include the native Shepherd's-purse (C. bursa-pastoris) and the introduced Pink Shepherd's-purse (C. rubella).

Two Diptera miners, the polyphagous agromyzids Chromatomyia horticola and Liriomyza strigata, are recorded on Capsella in Britain, and one of these is also recorded on Conringia, Hesperis, Lepidium and Raphanus.

Elsewhere the agromyzids Chromatomyia horticola, Liriomyza bryoniae, Liriomyza huidobrensis, Liriomyza strigata and Liriomyza trifolii and the drosophilid Scaptomyza flava are recorded mining Capsella.

No non-Diptera miners are recorded on Capsella in Britain.

Elsewhere two British non-Diptera mines, Ceutorhynchus minutus and Cnephasia incertana, are recorded on Capsella (see below)

A key to the European miners, based on characteristics of the mines, immature stages and where relevant the larval cases, recorded on Capsella is provided in Bladmineerders van Europa. This includes Chromatomyia horticola, Liriomyza bryoniae, Liriomyza strigata, Liriomyza xanthocera, Scaptomyza flava, Ceutorhynchus chalibaeus, Ceutorhynchus erysimi, Ceutorhynchus minutus, Phyllotreta nemorum, Plutella xylostella, Cnephasia incertana.

N.B. The key to mines below includes mines recorded on Alliaria, Armoracia, Barbarea, Brassica, Capsella, Cochlearia, Coincya, Conringia, Diplotaxis, Hesperis, Lepidium (= Cardaria), Raphanus, Sinapis, Sisymbrium and Thlaspi (Brassicaceae).

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: Details of mine unknown.

On Alisma and Rorippa nasturtium-aquaticum in Britain or elsewhere (record provenance ambiguous), but not yet on other Brassicaceae. Recorded in South Hants in Britain. Widespread in continental Europe.

Hydrellia meigeni Zatwarnicki, 1988 [Diptera: Ephydridae].

1# > Leaf-miner: Details of mine unknown.

On Rorippa nasturtium-aquaticum in Britain or elsewhere (record provenance ambiguous), but not yet on other Brassicaceae. South Hants and Surrey in Britain. Widespread in continental Europe.

Hydrellia pubescens Becker, 1926 [Diptera: Ephydridae].

1# > Leaf-miner: Details of mine unknown.

On Rorippa nasturtium-aquaticum in Britain or elsewhere (record provenance ambiguous), but not yet on other Brassicaceae. Cambridge in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe

Hydrellia ranunculi Haliday, 1839 [Diptera: Ephydridae].

1a > Leaf and stem miner: Oviposition takes place in the leaf blade where a short mine is formed until the larva reaches the nearest vein which is then followed downwards, with the main feeding occurring in the mid-rib, petiole, or in young plants, also in the stem. Puparium yellow

Only on Brassica, but not yet on other Brassicaceae, in Britain and additional genera of Brassicaceae elsewhere. Widespread but only recorded from Warwick, Dunbarton and East Lothian in Britain. Also recorded in the Republic of Ireland, continental Europe, Egypt, Canada and the U.S.A.

Phytomyza rufipes Meigen, 1830 [Diptera: Agromyzidae].

1b > Leaf-miner: Mine entirely in leaf, not in the petiole or stem.

2

2a > Leaf-miner: Mine primarily associated with mid-rib.

3

2b > Leaf-miner: Mine not primarily associated with mid-rib.

4

3a > 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 (Bladmineerders van Europa). A linear mine on the upper surface, usually following the midrib and showing side branches along the veins. The frass is in strings (British leafminers).

On more than 40 host genera in 15 families, including Brassica and Capsella, but not yet on other Brassicaceae, in Britain. Widespread throughout Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe.

Liriomyza strigata (Meigen, 1830) [Diptera: Agromyzidae].

3b > Leaf-miner: Corridor-blotch mine, normally dorsal; usually whitish; in small leaves it lies characteristically in the centre of the leaf often touching the petiole; in larger leaves it lies to one side of the mid-rib. Frass deposited in green clumps near the leaf margin. Pupation usually external, sometimes in a separate pupation mine.

On numerous genera of Brassicaceae, Asteraceae, Papaveraceae, Resedaceae, Tropaeolaceae and Violaceae, including Alliaria, Barbarea, Brassica, Cheiranthus, Cochlearia, Coincyia, Conringia, Diplotaxis, Erysimum, ? Hesperis. Lepidium, Mathiola, Raphanus, ? Rorippa and Sinapis, but not yet on Armoracia, Capsella, Sisymbrium and Thlaspi in Britain and additional genera of these families and Fabaceae. Widespread, from Caithness in the north to Cornwall in the south of Britain. Also recorded in the Republic of Ireland, Europe, the East Palaearctic, Near East and Neartic Region.

Scaptomyza flava (Fallén, 1823) [Diptera: Drosophilidae].

4a > Leaf-miner: Narrow corridor, leading to a large blotch. The blotch has lower- and upper-surface parts, and is full depth where these overlap. Pupation external

On ? Brassica, ? Sisymbrium, Stellaria and Potamogeton, but not yet on other Brassicaceae, in Britain and ? Stellaria elsewhere,Widespread from Caithness in the north to Kent in the south-east of Britain. Widespread in continental Europe.

Scaptomyza griseola (Zetterstedt, 1847) [Diptera: Drosophilidae].

4b > Leaf-miner: A long, narrow, winding corridor running towards the midrib, widening to a blotch. 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)

On ? Amaranthus, ? Rorippa, Cerastium, Lychnis, Myosoton, Silene, Stellaria, Atriplex, ? Anthyllis, ? Lupinus, ? Medicago, ? Montia and ? Antirrhinum, but not yet on other Brassicaceae, in Britain and Amaranthus, Lepidium, Moricandia, ? Rorippa, Agrostemma, Arenaria, Cerastium, Coronaria, 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.

Scaptomyza graminum (Fallén, 1823) [Diptera: Drosophilidae].

4c > 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 are polyphagous and widespread in Britain and elsewhere, although syngenesiae is almost entirely restricted to Asteraceae (see also 'atricornis').

Chromatomyia horticola is recorded on 55 plant genera in 19 families in Britain including Alliaria, Armoracia, Brassica, Capsella, Cheiranthus, Coincyia, Conringia, Hesperis, Lepidium, Sinapis, Sisymbrium, and Thlaspi in Britain.

Chromatomya syngenesiae is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, but not yet on Brassicaceae, in Britain.

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

4d > Leaf-miner: Irregular mine, locally shallow, elsewhere much deeper, giving it a mottled appearance. In broadleaved plants the mine often begins as a blotch with stellate extensions, but sometimes as a very fine, shallow corridor. In grasses the mine often begins in the leaf sheath. The frass is very fine-grained, initially scattered, later in aggregates.

Mine of Hydrellia griseola on Glyceria fluitans Image: Willem Ellis (Bladmineerders van Europa)

On ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum , ? Lychnis, ? Stellaria, ? Carex, ? Cyperus, ? Scirpus, ? Hydrocharis, ? Stratiotes, ? Lamium, ? Lemna, ? Allium, Arrhenatherum, ? Polygonum, ? Potamogeton, ? Veronica, ? Typha, but not yet on other Brassicaceae, in Britain and ? Alisma, ? Damasonium, ? Sagittaria, ? Bellis, ? Rorippa, Tropaeolum, Lychnis, ? Stellaria, Carex, ? Scirpus, Trifolium, ? Hydrocharis, Lamium, ? Lemna, Allium, Papaver, Agrostis, Alopecurus, Apera, Arrhenatherum, Avena, Avenula, Brachypodium, Briza, Bromus, Calamagrostis, Dactylis, Desmazeria, Digitaria, Echinochloa, Eleusine, Elymus, Festuca, Gaudinia, Glyceria, Holcus, Hordeum, Lagurus, Lolium, Panicum, Phalaris, Phleum, Phragmites, Poa, Secale, Setaria, Triticum, ? Polygonum, ? Potamogeton, Veronica, ? Typha and Verbena elsewhere. Widespread in England. Also recorded in the Republic of Ireland. Widespread in the Palaearctic region. Also recorded from Nearctic and Australasian Regions.

Hydrellia griseola (Fallén, 1813) [Diptera: Ephydridae]

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

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).

1a > Leaf-miner: Rather small, untidy, full depth, often branched corridor, often close to the leaf margin. Sides irregularly eaten out. Frass in a greyish-green central line that is interrupted from time to time, sometimes partly in strings. In times of rain the frass may run out and appear greenish. Usually several mines in a leaf (Bladmineerders van Europa). The legless larva is rather shapeless, with a well-sclerotised head. The body is whitish; head greyish brown with Y-shaped lighter marking. Pronotum with a pair of brownish shields. The mandibles have two teeth (Bladmineerders van Europa).

Mine of Ceutorhynchus minutus on Raphanus sativus Image: Willem Ellis (Bladmineerders van Europa)

Recorded on numerous genera and species of Brassicaceae, Capparaceae, Resedaceae and Tropaeolaceae, including Cochlearia, but not yet on Capsella, in Britain and Capsella, elsewhere. Widespread in Britain and continental Europe. Also recorded in the Republic of Ireland.

Ceutorhynchus minutus (Marsham, 1802) [Coleoptera: Curculionidae]

 

1b > 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 plant families, but not yet on Capsella, in Britain. Recorded on numerous genera and species of plant families including Capsella elsewhere. Widespread in Britain and continental Europe. Also recorded from the Channel Is.

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