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


Phytomyza obscura Hendel, 1920
[Diptera: Agromyzidae]

Phytomyza obscura Hendel, 1920. Arch. Naturgesch. 84A(7) (1918): 168
Phytomyza obscura Hendel, 1920; Spencer, 1972b. Handbk ident. Br. Ins. 10(5g): 71, 90, 116
Phytomyza obscura Hendel, 1920; Spencer, 1990. Host specialization in the World Agromyzidae (Diptera) : 205, 207, 208 (figs 770-1).

Leaf-miner: Mine beginning with a small spiral, later developing into a greenish blotch, brown when old. Pupation frequently in mine (Spencer, 1972b: 90).

The mine, that may be upper- or lower-surface, generally starts with a tight spiral. Its loops are so tight that the leaf tissue dies off and turns red; nevertheless the corridor remains well visible. Later the corridor widens and finally a large secondary blotch develops around the initial spiral. Frass at first in two rows of grains, later in pearl chains. Feeding lines very clear. Pupation now within, then 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.

The larva is described by de Meijere (1926); posterior spiracles each with approx. 13-15 bulbs in a quarter circle (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 on lower protuberance larger, each with 26-28 bulbs (Spencer, 1972b: 90).

Comments: Spencer (1990: 207) states that Phytomyza obscura is host-specific on Satureja. S. vulgaris is a junior synonym of Clinopodium vulgaris, which is the host plant given by Spencer (1972b: 116).

Hosts in Great Britain and Ireland:

Clinopodium       Robbins, 1991: 100
Clinopodium       Spencer, 1990: 207, as Satureja.
Clinopodium ascendens Common Calamint British Wild Flowers by John Somerville et al. Pitkin & Plant
Clinopodium vulgare Wild Basil British Wild Flowers by John Somerville et al. Spencer, 1972b: 116
Mentha       Pitkin & Plant
Nepeta       Pitkin & Plant

Hosts elsewhere:

Clinopodium vulgare Wild Basil British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Clinopodium vulgare Wild Basil British Wild Flowers by John Somerville et al. Nowakowski, 1959
Satureja glandulosa     Bladmineerders van Europa

Time of year - mines: June, September.

Time of year - adults: Currently unknown.

Distribution in Great Britain and Ireland: ? Oxfordshire (Oxford) (Spencer, 1972b: 90).

Distribution elsewhere: Widespread in continental Europe including Austria, Azores, Bulgaria, Canary Is., Czech Republic, Germany, Hungary, Italian mainland, Lithuania, Madeira, Poland, Slovakia and Spanish mainland (Fauna Europaea).

NBN Atlas links to known host species:

Clinopodium ascendens, Clinopodium vulgare

British and Irish Parasitoids in Britain and elsewhere:

Chrysocharis orbicularis (Nees, 1834) Eulophidae: Entedoninae
Chrysocharis pubicornis (Zetterstedt, 1838) Eulophidae: Entedoninae
Ichneumonoidea - Links to species no longer available  
Chorebus nanus (Nixon, 1943) Braconidae: Alysiinae
Apodesmia similis (Sz├ępligeti, 1898) Braconidae: Opiinae
Eurytenes abnormis (Wesmael, 1835) Braconidae: Opiinae
Opius gracilis Fischer, 1957 Braconidae: Opiinae
Opius pallipes Wesmael, 1835 Braconidae: Opiinae

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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