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

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Agromyza varicornis Strobl, 1898
[Diptera: Agromyzidae]

Agromyza varicornis Strobl, 1898b. Wiss. Mitt. Bosn. Herzeg. 7: 640 (as a var. of abiens Zetterstedt)
Agromyza watersi Spencer, 1957c. Commentat. biol. 16(4): 1
Agromyza varicornis Strobl, 1898b; Spencer, 1972b. Handbk ident. Br. Ins. 10(5g): 42, 117
Agromyza varicornis Strobl, 1898b; Spencer, 1990. Host specialization in the world Agromyzidae (Diptera) : 112, 127, 129 (fig 468).


Mine of Agromyza varicornis on Lathyrus latifolius. Image: Colin Plant (British leafminers)
Mine of Agromyza varicornis on Lathyrus latifolius
Image: © Colin Plant (British leafminers)

Leaf-mine: A long white mine mainly in the winged stem, frequently starting in leaf (Spencer, 1972b: 42).

The mine begins as a narrow under-surface corridor. It usually quickly becomes upper-surface, and also the following blotch part of the mine is upper-surface. Here and there in the blotch the larvae also eats from the palisade parenchyma, giving the mine a mottled aspect when held against the light, but less strongly than in A. lathyri. Frass in the initial corridor, if at all visible, in short threads; very little frass in the blotch. Pupation outside the mine (Bladmineerders van Europa).

The mine is in the wing of the stem, but often starts in leaf (though not always) (British leafminers).

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 Hering (1957). Posterior spiracles each with 3 bulbs (Spencer, 1972b: 42 and 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).

Posterior spiracles each with 3 bulbs (Spencer, 1972b: 42).

Hosts in Great Britain & Ireland:

Fabaceae        
Lathyrus latifolius Broad-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Robbins, 1991: 46
Lathyrus latifolius Broad-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Spencer, 1972b: 117
Lathyrus latifolius Broad-leaved Everlasting-pea British Wild Flowers by John Somerville et al. British leafminers
Lathyrus sylvestris Narrow-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Mines in BMNH
Lathyrus sylvestris Narrow-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Spencer, 1972b: 117

Hosts elsewhere:

Fabaceae        
Lathyrus       Spencer, 1990: 112
Lathyrus latifolius Broad-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Lathyrus sylvestris Narrow-leaved Everlasting-pea British Wild Flowers by John Somerville et al. Bladmineerders van Europa

Time of year - mines: June, August.

Time of year - adults: Currently unknown.

Distribution in Great Britain & Ireland: Widespread in Britain including London (Hampstead), Isle Of Wight (Luccombe), Cambridge (Cambridge), Denbighshire (Cefn-y-bedd) (Spencer, 1972b: 42) and Warwickshire (Coventry) (Robbins, 1991: 46). South Lancashire, Surrey, West Gloucestershire (NBN Atlas).

Distribution elsewhere: Widespread in continental Europe including Germany (Bladmineerders van Europa), Italian mainland, Lithuania, Spanish mainland and Yugoslavia (Martinez in Fauna Europaea).

NBN Atlas links to known host species:

Lathyrus latifolius, Lathyrus sylvestris

British and Irish Parasitoids in Britain and elsewhere: Currently unknown.



External links: Search the internet:
Biodiversity Heritage Library
Bladmineerders van Europa
British leafminers
Encyclopedia of Life
Fauna Europaea
NBN Atlas
NHM UK Checklist
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