Pulicaria [Asteraceae] in Leaf and stem mines of British flies and other insects

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

PULICARIA. Fleabanes. [Asteraceae]

Four species of Pulicaria are recorded in Britain. These include the native Small Fleabane (P. vulgaris) and Common Fleabane (P. dysenterica).

Small Fleabane (P. vulgaris) is protected under Schedule 8 of the Wildlife and Countryside Act, 1981.

Six or seven British miners are recored on Pulicaria.

A key to the European miners recorded on Pulicaria is provided in Bladmineerders van Europa.

Common Fleabane
Pulicaria dysenterica

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

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, usually in a lower-surface puparial chamber.

A long whitish upper surface corridor, which eventually goes lower surface.

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 syngenesiae is recorded on 160 plant genera in 31 families, of which 55 plant genera in 19 families, but not yet on Pulicaria, in Britain or elsewhere.

Chromatomya 'atricornis' is recorded in Britain on 27 plant genera in the family Asteraceae and many more genera elsewhere, including ? Pulicaria, in Britain.

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

1b > Leaf-miner: An irregularly linear mine which can be both on the upper and lower leaf surface. Pupation takes place either at the end of the mine in an exit slit cut in the leaf or on the ground (Spencer, 1972b: 70 (fig. 226), 73; Spencer, 1976: 407 (fig. 712), 408).

Upper surface corridor, often following the midrib for some distance. Frequently the very first part of the mine is lower-surface, and sometimes the entire mine remains at the lower surface. The corridor is wide from the start, with irregular sides. Frass initially in two rows of fine grains; further on the grains become larger and more irregular, sometimes forming pearl chains, and are dispersed less regularly. Pupation takes place either outside or within the mine. When the larva has left the mine a semicircular exit slit is made. When the puparium is formed within the mine the spiracles do not penetrate the epidermis, and an irregular semicircular opening is made in the epidermis in front of the puparium.

Mines down the leaf from the tip, then doubles back and then mines towards the apex, often doubling back a second time, towards the leaf base.

On Inula and Pulicaria in Britain and additional genera of Asteraceae elsewhere. Widespread in Britain. Also recorded in the Republic of Ireland. Widespread in continental Europe and particularly common in the Mediterranean area

Phytomyza conyzae Hendel, 1920 [Diptera: Agromyzidae].

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

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, but not a case-bearer. The larva mines the leaves, forming brownish or whitish inflated blotches. Whitish or brownish full depth blotch, preceded by a short corridor that originates on the midrib or in the leaf base. Frass grains irregularly dispersed; part of the frass is ejected from the mine. The larva makes several mines. Pupation outside the mine.

On Inula and Pulicaria in Britain and elsewhere. Locally distributed, occurring from southern England northwards to Northumberland and west to Wales. Also recorded in Republic of Ireland. Widespread in continental Europe.

Digitivalva pulicariae (Klimesch, 1956) [Lepidoptera: Acrolepiidae].

1b > Leaf-miner and case-bearer

2a > Leaf-miner and case-bearer: The larva makes at least two cases and leaves the empty case by the cut out leaf section. The early cases are compressed with keels, dorsally and laterally. Later cases are more tubular and hairy (from the hairy leaves, used to make the case). Larva in a spathulate leaf case. It is 10-12 mm long, straght, brown, tubular, patently hairy (depending on the hostplant), bivalved. The mouth angle is rather variable, usually around 45°. An unusual character of this species is that after each moult the larva makes a new case; the old, vacated case is left at the place where the new one is made, at the leaf margin.

On Eupatorium, Inula and Pulicaria in Britain and elsewhere. Mainly distributed in southern England and Wales. A colony has also been located in York, so it may occur elsewhere. Widespread in continental Europe.

Coleophora conyzae Zeller, 1868 [Lepidoptera: Coleophoridae].

2b > Leaf-miner and case-bearer: Larva mines leaves. On Eupatorium the case is extended at the anal end by adding silk and widened by cutting a ventral gusset. On Inula the case is firstly extended by adding rings of leaf-cuticle at the oral end, before reverting to the method used when on Eupatorium. The full-grown case is 10 mm long. A slender tubular silken case, about 10 mm long, straw coloured, three valved. Mouth angle about 30°.

On Cirsium, Eupatorium, Inula and Pulicaria in Britain and Achillea, Anthemis, Carduus, Cirsium, Eupatorium, Inula, Leucanthemum, Pulicaria and Tanacetum elsewhere. Widespread in England. Also recorded in Republic of Ireland. Widespread in continental Europe.

Coleophora follicularis (Vallot, 1802) [Lepidoptera: Coleophoridae].

2c > Leaf-miner and case-bearer: The larva builds a 'pistol case'. The mature case is around 15mm long with a slightly swollen middle region, being palest at the anal end. Larva in a slender tubular silken case. The case is about 15 mm long, yellow-grey, and trivalved. The mouth angle is about 0°-10°, causing the case to lie flat on the leaf.

On Inula and Pulicaria in Britain and Eupatorium, Inula and Pulicaria elsewhere. A scarce and very local species which has a small number of tiny colonies in the south of England, principally in Hants and the Isle of Wight. Widespread in continental Europe.

Coleophora inulae Wocke, 1877 [Lepidoptera: Coleophoridae].


	Last updated 06-Jul-2019 Brian Pitkin