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


Agromyza ambigua Fallén, 1823
[Diptera: Agromyzidae]

Agromyza ambigua Fallén, 1823a. Agromyzides Sveciae : 4
Phytomyza niveipennis Zetterstedt, 1848. Dipt. Scand. 7: 2742
Agromyza ambigua Fallén, 1823a; Spencer, 1972b. Handbk ident. Br. Ins. 10(5g): 10, 30 (fig.78), 33, 124
Agromyza ambigua Fallén, 1823a; Spencer, 1976; Spencer, 1990. Host specialization in the world Agromyzidae (Diptera) : 354, 356, 359, 361, 364.

Leaf-miner: Leaf-mine normally short and broad (Spencer, 1976: 97). According to Hering (1957) initially the larva does not feed towards the apex of the leaf. Pupation external (Spencer, 1976: 97).

The shallow, whtish mine starts (not very close to the base of the lamina) as a fine ascending corridor. This is overrun when the direction alternates, and the mine quickly widens. The final mine is characteristically short; often not the full width of the leaf is used. Frass in big black grains, never greenish. Pupation outside the mine (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.

Larval mandibles with three teeth; posterior spiracles each with 3 bulbs (Hering, 1953).

The mandible with two normal teeth, and a smaller additional basal one (Hering, 1953a). The girdles of fine spinulation along the anterior and posterior margins of the body segments normal, i.e., relatively narrow, nowhere fusing together (unlike in A. nigrociliata). Rear spiracula far apart, each with 3 bulbs. Behind the mandibles ventrally a median field with fine spines (character of the Agromyza ambigua group of Griffiths, 1963a).The larva is also illustrated by Beri (1971c), based on material from India, living on a Setaria species. However, he describes the left mandible as having 2, the right one 1 tooth, which makes it questionable if he had the European species in front of him (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).

Yellowish-brown; posterior spiracles each with 3 bulbs, processes widely separated (Spencer, 1976: 97).

Hosts in Great Britain and Ireland:

Avena sativa Oat   Spencer, 1972b: 122
Hordeum vulgare Six-rowed Barley   Mines in BMNH
Secale cereale Rye   Spencer, 1972b: 124

Hosts elsewhere:

Avena       Spencer, 1990: 354
Avena sativa Oat   Spencer, 1976: 97
Avena sativa Oat   Bladmineerders van Europa
Elytrigia       Spencer, 1990: 356, as Agropyron
Hordeum       Spencer, 1990: 356
Hordeum murinum Wall Barley British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Hordeum vulgare Six-rowed Barley   Spencer, 1976: 97
Hordeum vulgare Six-rowed Barley   Bladmineerders van Europa
Secale       Spencer, 1990: 356
Secale cereale Rye   Spencer, 1976: 97
Secale cereale Rye   Bladmineerders van Europa
Triticum       Spencer, 1990: 356
Triticum aestivum Bread Wheat   Spencer, 1976: 97
Triticum aestivum Bread Wheat   Bladmineerders van Europa

Time of year - mines: July.

Time of year - adults: Currently unknown.

Distribution in Great Britain and Ireland: Widespread, but local - Kent (Thames Marshes) (Spencer, 1972b: 33), Aberdour and Bonhill (Spencer, 1956) and Outer Hebrides (North Uist) (Bland, 1994b). Ayrshire (NBN Atlas)

Distribution elsewhere: Common and Widespread in continental Europe (Spencer, 1990) including The Netherlands (Bladmineerders van Europa), Denmark, Sweden, Finland (Spencer, 1976: 97), Germany (Spencer, 1976: 546) Canary Is., Czech Republic, Hungary, Italian mainland, Sicily, Slovakia, Spanish mainland, Switzerland and Yugoslavia (Fauna Europaea).

Also recorded in Canada and America (Spencer, 1969a: 35; Spencer, 1990).

NBN Atlas links to known host species:

Avena sativa, Hordeum vulgare, Hordeum murinum, Secale cereale, Triticum aestivum

British and Irish Parasitoids in Britain and elsewhere:

h/projects/chalcidoids/database/validName.dsml?index=ValidName&searchPageURL=indexValidName.dsml&sep=SEP&Genusqtype=equals&GenusVal=Cirrospilus&Genus=Cirrospilus&Speciesqtype=equals&SpeciesVal=vittatus&Species=vittatus" target="_blank">Cirrospilus vittatus Walker, 1838
Ichneumonoidea - Links to species no longer available  
Eurytenes maculipes Wesmael, 1835 Braconidae: Opiinae
Rhogadopsis reconditor Wesmael, 1835 Eulophidae: Eulophinae
Diglyphus chabrias (Walker, 1838) Eulophidae: Eulophinae
Pnigalio pectinicornis (Linnaeus, 1758) Eulophidae: Eulophinae
Ichneumonoidea - Links to species no longer available  
Chorebus credne (Nixon, 1944) Braconidae: Alysiinae

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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