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 Norway: Tachinidae - Tachina magnicornis ♂ ? => Tachina fera ♀
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| Jorn R Gustad |
Posted on 17-07-2017 09:34
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Observed and subsequently sweep netted 15th July in my garden located in coastal farmland at 63 degrees N 32 m asl. I suspect it to be a male, and a magnicornis rather than fera. Both species are occurring in Norway, the latter being more common/widespread, but the records are probably somewhat ambiguous. Any help appreciated as always! Cheers Jørn Jorn R Gustad attached the following image:  [284.95Kb] Edited by Jorn R Gustad on 17-07-2017 19:28 |
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| Jorn R Gustad |
Posted on 17-07-2017 09:36
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Dorsal
Jorn R Gustad attached the following image:  [266.96Kb] |
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| Jorn R Gustad |
Posted on 17-07-2017 09:36
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Head
Jorn R Gustad attached the following image:  [270.68Kb] |
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| Jorn R Gustad |
Posted on 17-07-2017 09:47
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Tip of abdomen
Jorn R Gustad attached the following image:  [300.02Kb] |
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| John Carr |
Posted on 17-07-2017 11:58
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 Member Location: Massachusetts, USA Posts: 9839 Joined: 22.10.10 |
I think I see median marginals on tergite 2. |
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| Jorn R Gustad |
Posted on 17-07-2017 18:53
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Thanks John, I am so inexperienced in the clinal terms of Diptera, so I do not understand in which way your comment directs. Please elaborate. I find the specimen to match the abdomen, claw and oe features for magnicornis in key of Tschorsnig & Herting, 1994 - translated by Rayner & Raper (2001), but I am unsure if the frons are broad enough for it, or if the frons points to fera. An experienced eye might tell? Citation, from page 50: Frons in males 0.68 - 1.08x, in females 0.94 - 1.28x as wide as one eye. Fore tarsus yellow, seldom brown. The black longitudinal abdominal stripe ends almost always in a tip on tergite 5. Males: anterior claws almost as long as the last 2 tarsal segments combined (fig. 146); frons as a rule without oe, seldom 1 oe present .................................................................................................................................. fera L. − Frons in males 1.10 - 1.39x, in females 1.27 - 1.55x as wide as one eye. Fore tarsus brown or black. Males: anterior claws clearly shorter than the last 2 tarsal segments combined; frons with 1 or 2 oe ....................7 7. The black longitudinal abdominal stripe widens towards the end on tergite 5, seldom ending in a point. Males: anterior claws longer than the last tarsal segment. Females: 4th segment of the fore tarsus clearly wider than long..................................................................................................................magnicornis Zett. Edited by Jorn R Gustad on 17-07-2017 19:02 |
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| Zeegers |
Posted on 17-07-2017 19:05
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Member Location: Soest, NL Posts: 18518 Joined: 21.07.04 |
It is a female, the claws are much too short for a male. Females are very difficult. But in this case, the metatarsi are red, so I have little doubt it is fera. The shape of the abdominal vitta is highly unreliable. Theo |
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| Jorn R Gustad |
Posted on 17-07-2017 19:26
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Member Location: Averøy, Norway Posts: 166 Joined: 26.12.11 |
Thanks, Theo! [Edit] I wrongly looked at the foreleg claws, not the hind leg (anterior) claws... I also understand that that all tarsomeres needs to be dark, and have probably greatly misunderstood the oe - outer orbital bristles problematics. Anyway - I will not give up! Cheers Jørn Edited by Jorn R Gustad on 17-07-2017 19:37 |
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| Zeegers |
Posted on 17-07-2017 21:02
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Member Location: Soest, NL Posts: 18518 Joined: 21.07.04 |
You should look at the fore claws, indeed, although you can use any in this case. But in males it is much longer. Since all females have 2 pairs of proclinate orbitlas, the feature is only relevant for males. The vertex is broad for a male, but narrow for a female .... so sexing right is crucial here Theo |
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but don't see the image in the post.
