Petasites [Asteraceae]

PETASITES. Butterburs and Winter Heliotrope. [Asteraceae]

Five species of Petasites are recorded in Britain. These included the native Butterbur (P. hybridus) and the introduced Winter Aconite (P. fragrans).

Three Diptera miners, the agromyzid Phytomyza tussilaginis and the tephritids Acidia cognata and Trypeta zoe and are recorded on Petasites in Britain.

Elsewhere the agromyzids Liriomyza huidobrensis, Phytomyza buhriella and Phytomyza tussilaginis, the anthomyiid Pegomya depressiventris, and the tephritids Acidia cognata, Stemonocera cornuta and Trypeta zoe are recorded mining Petasites.

No non-Diptera leaf-miners are recorded on Petasites in Britain.

Butterbur
Petasites hybridus

Elsewhere one British non-Diptera miner is recorded on Petasites (see below).

The pterophorid Platyptilia gonodactyla is recorded as a stem and flower feeder on Petasites in Britain.

Key for the identification of the mines of British Diptera recorded on
Petasites

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).

1a > Leaf-miner: 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].

1b > Leaf-miner: 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].

1c > Leaf-miner: 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].

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

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).

1 > Leaf-miner: 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).

Recorded on Tussilago, but not yet on Petasites, 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]


	Last updated 07-Feb-2012 Brian Pitkin