Leaf-miner: A
narrow upper surface linear branching mine without apparent feeding
lines. Frass in isolated grains and pearl chains. At least in Erigeron
older mines turn reddish-brown. Pupation external (Spencer,
1976: 413; Bladmineerders van Europa).
Larva: The larvae of flies 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 larva is described by de Meijere (1928,
as erigerophila, 1937 as asteribia) and Griffiths
(1976c); posterior spiracles
each with 8-11 bulbs (Bladmineerders van Europa).
Puparium: The puparia of flies are 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).
Black; posterior spiracles on short conical projections, each with
an ellipse of about 13 bulbs (Spencer,
1976: 413).
Comments:
Erigeron acer is treated
as Erigeron acris (Blue
Fleabane) by Stace (2010).
Hosts in Great Britain and Ireland:
Hosts
elsewhere:
Time
of year - mines:
June-July and September (Hering,
1957).
Time
of year - adults: Currently unknown.
Distribution
in Great Britain and Ireland: Occurence in Britain first recorded
by Robbins (1989) and confirmed
by Deeming (1995). Warwickshire
(Hartshill and Ladywalk) (Robbins,
1991); Glamorgan (NBN
Atlas). Distribution elsewhere: Widespread in continental Europe, including Denmark, Finland,
France, Norway (Spencer, 1976:
413), The Netherlands (Bladmineerders van Europa), Germany (Spencer,
1976: 570), Bulgaria, Corsica, Czech Republic, Lithuania and
Poland (Fauna Europaea).
NBN Atlas links to known host species:
British and Irish Parasitoids in Britain and elsewhere: Currently unknown.
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