Diptera.info :: Identification queries :: Diptera (adults)
 Late autumn Sphaeroceridae, Oct.28, 2006
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| Dmitry Gavryushin |
Posted on 30-10-2006 13:34
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 Member Location: Moscow region, Russia Posts: 3338 Joined: 17.10.05 |
I took a walk in a forest last Saturday and saw a lot of small dark flies gliding on water surface of a small pool (actually it was a car track filled with water) on the edge of a mixed forest. It was around 5 degrees or even less, but they were quite active. I collected some using a film box, thinking it's Ephydridae. But when I took some pictures at home I understood they were Shaeroceridae, size 1.5 to 2mm. I've contacted Dr. Roh?ček on this matter, and here's his comment: Yes, I know this species imitating Ephydridae very well and I also observed it running on water surface (most often in autumn). It is Pseudocollinella humida (Haliday, 1836), a common species associated with muddy shores of waters but often found also along small creeks on gravel dirted by mud etc. In contrast to Leptocera and Rachispoda it only has 4 (2 pairs) scutellars, 1 pair of strong acrostichals, and less rich mid tibial chaetotaxy. The female can be easily recognized by strong blunt spine-like seta on apex of cercus.
Dmitry Gavryushin attached the following image:  [168.47Kb] |
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| Nikita Vikhrev |
Posted on 30-10-2006 14:18
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 Member Location: Moscow, Russia Posts: 9475 Joined: 24.05.05 |
Dima, next step is to persuade Dr. Rohachek to registrate as a new member of Diptera.info. Do it, please!
Nikita Vikhrev - Zool Museum of Moscow University |
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| Dmitry Gavryushin |
Posted on 30-10-2006 14:40
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Member Location: Moscow region, Russia Posts: 3338 Joined: 17.10.05 |
Well I'd love to if I only could...  We all need even more interesting posts to allure more experts... or become experts ourselves  |
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| Kahis |
Posted on 30-10-2006 16:24
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 Member Location: Helsinki, Finland Posts: 1999 Joined: 02.09.04 |
I'd say Pseudocollinella humida, but who knows what Russian species may look similar. Well, Dr. Rohachek obviously does, so you'd better ask him
Edited by Kahis on 30-10-2006 16:24 Kahis |
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| Kahis |
Posted on 30-10-2006 16:28
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Member Location: Helsinki, Finland Posts: 1999 Joined: 02.09.04 |
Features to look for in this case are: Only 4 major setae of scutellum, no hairs; two strong presutural acrostichal setae; middle basitarsus (1st segment of 2nd tarsus) with a strong seta on lower side - poorly visible in the photo but I think it's there; whitish dusting on face; mid tibiae without very long setae. It does help to know that this species is very common on small patches of mud, together with the ephydrid Scatella and a few species of the spaherocerids Rachispoda and Leptocera. Edited by Kahis on 30-10-2006 16:31 Kahis |
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