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

 

Cerodontha iridis (Hendel, 1928)
[Diptera: Agromyzidae]

Dizygomyza iridis Hendel, 1928. Blattminenkunde Europas. I. Die Dipterenminen. Wien: 53
Cerodontha (Dizygomyza) iridis (Hendel, 1927); Spencer, 1972b. Handbk ident. Br. Ins. 10(5g): 100
Cerodontha (Dizygomyza) iridis (Hendel, 1927); Spencer, 1990. Host specialization in the world Agromyzidae (Diptera) : 331, 332 (figs 1266-7), 336.


Leaf-miner: A number of larvae feeding together to form a conspicuous, mottled greenish mine. Pupation laterally across the leaf at end of mine (Spencer, 1972b: 100).

Two to 12 eggs are separately inserted in a leaf, not far from the apex. The young larvae begin making a short, narrow, corridor that runs upwards. Soon the direction reverses, the corridors quickly become wider and fuse. The result is a large blotchy mine, generally containing several larvae. The mine is very inconstant in depth, making it vary, when seen by transparency, from green to almost vitreous. Mines contain several lumps of frass. Pupation in the mine. The pupariria lie close together in a row, in the lowest part of the mine, oriented perpendicularly to the leaf (Bladmineerders van Europa).

Forms a blotch mine, which may be large when several mines coalesce (British leafminers).

Mines of Cerodontha iridis on Iris foetidissima Image: Gabrijel Seljak,  Slovenië (Source: Bladmineerders van Europa)

Mines of Cerodontha iridis on Iris foetidissima
Image: © Gabrijel Seljak (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 Nowakowski (1973).

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).

The puparium is illustrated in Bladmineerders van Europa.

Hosts in Great Britain and Ireland:

Iridaceae        
Iris       Robbins, 1991: 130
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. Mines in BMNH
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. British leafminers
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. Robbins, 1991: 130
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. Spencer, 1972b: 125
Iris ochroleuca Seaside Iris   Spencer, 1972b: 100
Iris ochroleuca Seaside Iris   British leafminers
Iris spuria Blue Iris   British leafminers
Iris spuria Blue Iris   Spencer, 1972b: 100

Hosts elsewhere:

Iridaceae        
Iris       Spencer, 1990: 336
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. Bladmineerders van Europa
Iris foetidissima Stinking Iris British Wild Flowers by John Somerville et al. Spencer, 1990: 331
Iris ochroleuca Seaside Iris   Bladmineerders van Europa

Time of year - mines: Early Autumn (British leafminers).

Time of year - adults: Currently unknown.

Distribution in Great Britain and Ireland: Abundant throughout southern counties (Spencer, 1972b: 100) including Gloucester (Cheltenham) (British leafminers); Isle of Wight, Radnorshire, South-west Yorkshire, Surrey and West Gloucestershire (NBN Atlas).

Distribution elsewhere: Widespread in western Europe including French mainland, Germany, Hungary, Italian mainland and Portuguese mainland (Fauna Europaea).

NBN Atlas links to known host species:

Iris foetidissima, Iris ochroleuca

British and Irish Parasitoids in Britain and elsewhere:

Chalcidoidea   
Hemiptarsenus unguicellus (Zetterstedt, 1838) Eulophidae: Eulophinae
Ichneumonoidea - Links to species no longer available  
Dacnusa maculipes Thomson, 1895 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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Find images using Google


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