Diptera.info :: Family forums :: Syrphidae
 Dark E. balteatus
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| pierred |
Posted on 07-06-2007 20:51
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 Member Location: Paris (France) Posts: 1484 Joined: 21.04.05 |
Hello, Well, while taking pictures of any living being, as usual, I came across this one. In the first time, I thought this was a E. balteatus, but found it too dark indeed. I further photographed, thinking I would be able to sort the matter out. As a matter of fact, I think this is a dark form of E. balteatus. Any objections ? pierred attached the following image:  [92.22Kb] Edited by pierred on 07-06-2007 20:52 Pierre Duhem |
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| Gerard Pennards |
Posted on 07-06-2007 22:00
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 Member Location: Amersfoort Posts: 1914 Joined: 07.06.04 |
Yes, this is a dark specimen of Episyrphus balteatus. Mostly it happens when something disturbes their pupal stage, like a too high or low temperature! greetings, Greetings, Gerard Pennards |
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| pierred |
Posted on 08-06-2007 06:28
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Member Location: Paris (France) Posts: 1484 Joined: 21.04.05 |
Gerard, Thanks for the explanation. Pierre Duhem |
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| pierred |
Posted on 12-06-2007 06:17
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Member Location: Paris (France) Posts: 1484 Joined: 21.04.05 |
Hello, I posted this picture in the Gallery and Paul labelled it "intersex". Could you explain, Paul? Pierre Duhem |
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| Paul Beuk |
Posted on 12-06-2007 06:43
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 Super Administrator Location: Netherlands Posts: 19403 Joined: 11.05.04 |
When you examine the head, you will see that the eyes are separate (so not a male) but they are closer together than in 'regular' females. In several species similar specimens can be found and these always have a darker abdomen or the pattern is even completely absent (e.g., 'Scaeva unicolor' . Internal examination has revealed that these specimens, though mostly resembling females, have no ovarioles and neither do they have male genitalia. I am not aware of any examination of chromosomes, but these specimens appear to be neither male not female and have often been labeled as 'intersex'.
Paul - - - - Paul Beuk on https://diptera.info |
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| pierred |
Posted on 12-06-2007 16:26
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Member Location: Paris (France) Posts: 1484 Joined: 21.04.05 |
Paul, Thanks for the precious information. That would mean that le cold weather (the cold/hot envrionment G. Pennards mentionned, in our case, is the little glaciation we had over the last two weeks) coud also provoke a misdevelpment of the sexual apparel ? Or are those aspects totally distinct? Pierre Duhem |
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