Diptera.info :: Identification queries :: Diptera (adults)
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 Genus Delia
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| RSB CEROM |
Posted on 05-06-2012 16:31
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Member Location: Posts: 3 Joined: 04.06.12 |
I currently work on the genus Delia and I need help for the identification...It is not easy! Firsly, I look on the differents posts and some of you are very good to identify with a picture. What are the caracteristics that you use for determine the genus Delia? I use Darvas B. and A. Szappanos key, Male and Female morphology of some central european Delia (Anthomyiidae) pest, and the caracteristics are for the genus: A1 extending to the wing margin (ok!), Lower calypter as large as or smaller tha upper one (ok!), The longest hairs on arista are distinctly shorter than the width of first flagellomere (...hum!? It is visible to the naked eyes?!). The plopleuron is bare (ok) and The apical posterobentral seta of the hind tibia is absent or hardly distinguishable from adjacent setulae...(picture please?!) for the male: Parafrontals without orbital setae. Fore Tibia without an anterodorsal seta. The Aedeagus is long and wll sclerotized...So What is your trick? Thanks a lot! I am completly confused  PS:I apologize for my english, it is not my first language!  RSB |
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| Stephen R |
Posted on 05-06-2012 18:13
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 Member Location: Clitheroe Lancashire UK Posts: 2396 Joined: 12.06.09 |
Hi RSB. Welcome to the forum! I think the first thing we have to accept is that there is no set of externally visible characters that defines the genus Delia. It is defined in terms of the form of the male genitalia, which are more or less completely hidden in photos of living flies and can only be properly examined with a microscope after dissection and preparation. There are some species or groups within Delia that can be recognised when a distinctive feature or combination of features is visible in photos (the group with a blunt curved apical spur on the fore-tibia is an example), but for most species you just can't tell until you have a specimen under the microscope. With photos of Delia, we are all confused  The key I use is by Michael Ackland. I believe he has withdrawn it pending a revision, but watch this space: http://tachinidae.../antho.php |
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| Michael Ackland |
Posted on 06-06-2012 09:10
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Member Location: Dorset UK Posts: 680 Joined: 23.02.08 |
Stephen, you could not have given a better answer! To RSB. Darvas B. and A. Szappanos key is only for a few cruciferous pests, and so will not be of much use for most Delia. Their characters for Delia are, I am afraid, mainly wrong. I use Hennig, Die Fliegen and various papers by Verner Michelsen, and Graham Griffiths Nearctic revision is very useful, as many species are Holarctic. useful and up to date I assume you are in Europe? To work on Anthomyiidae it is necessary to dissect the genitalia. Otherwise it is mostly guesswork. If you tell us what your aims are, I may be able to offer more advice. |
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| RSB CEROM |
Posted on 06-06-2012 14:34
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Member Location: Posts: 3 Joined: 04.06.12 |
Thanks a lot for your anwsers. I'm in the field of biological control in agriculture in canada, Quebec. I currentl work on seed treatment for seedcorn maggot (Delia platura, D. florigela and D. radicum) and I try to evaluate the real population of this fly. Because of the complexity to identified, I think that all the Anthomyiidae capturated is automatically identified genus Delia. With about 550 species of Anthomyiidae...The margin of error is large! I want to show the actual population of the pest to make better environmental choices. |
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| Michael Ackland |
Posted on 06-06-2012 17:16
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Member Location: Dorset UK Posts: 680 Joined: 23.02.08 |
You will find most of the answers you need in Griffiths, G.C. D. 1982-2004. Flies of the Nearctic Region, Vol VIII, Part 2, Cyclorrhapha II, Schizophora:Calyptratae, Anthomyiidae, Nos 1-15. Delia species are in Nos7,8,9,10. There is an up-to-date summary of biological pest control, keys and figures to the genitalia. There are several other cereal pests in the Nearctic, so you need to study the whole work! |
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