Thread subject: Diptera.info :: Episyrphus balteatus, melanistic and intersex?

Posted by bonitin on 29-11-2011 13:17
#1

Hi,:)

I have never seen a melanistic E.balteatus being so dark with hardly any marks left on its abdomen..
22nd November, my garden Gent, Belgium

Thank you!
Myriam

Posted by bonitin on 29-11-2011 13:19
#2

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Posted by bonitin on 29-11-2011 13:20
#3

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Posted by bonitin on 29-11-2011 13:24
#4

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Posted by bonitin on 29-11-2011 13:25
#5

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Posted by bonitin on 29-11-2011 13:27
#6

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Posted by Ectemnius on 29-11-2011 21:10
#7

To me this looks like a dark female specimen of E. balteatus.

It has no male genitalia and the eyes are separated...

E. balteatus can be as dark as this due to lower temperatures during pupation. If the temperatures are warmer one can find specimens which are almost entirely yellow.

Btw. very neat pictures.

Greets,

Ectemnius

Posted by blowave on 29-11-2011 21:44
#8

I am interested to know why this female has strange 'bumps' on the last segments of the abdomen Ectemnius.

Separated eyes seem to be no guarantee of being a female if you check the 'intersex' examples in the gallery.

http://www.dipter...to_id=2601

http://www.dipter...to_id=1678

I have a photo of one similar to the dark one in the last link which I thought could be an intersex.. I don't seem to be able to get the photo down to the acceptable size but here's the tail end..

Edited by blowave on 29-11-2011 21:45

Posted by blowave on 29-11-2011 21:47
#9

This is the tail end of what I would call a 'normal' female..

Edited by blowave on 29-11-2011 21:48

Posted by Ectemnius on 29-11-2011 22:24
#10

Hi bonitin,

I didn't know why you thought it was an intersex specimen. The abdomen is somewhat strange, I agree. But it don't look like an intersex specimen to me.

That having said, I'm no expert concerning intersex specimens, and the specimens in the gallery look awfully the same.
There seems to be confusion on the matter if you search for more info, even on diptera.info itself, as the two post below reveal.

Paul Beuk mentions that darker appearance and intersex in one specimen can be related:
http://www.diptera.info/forum/viewthread.php?thread_id=13048&pid=61129.

In yet another post Gerrard Pennards disagrees with a presumed intersex specimen:
http://diptera.info/forum/viewthread.php?thread_id=32361&pid=143572

Both have similar features to your specimen.

Just trying to help,

Greets,

Ectemnius

Posted by blowave on 29-11-2011 22:38
#11

Working links to the threads Ectemnius.. highlight and click on the icon below. :)

http://www.dipter...;pid=61129

http://diptera.in...pid=143572

The intersex was only mentioned in the title, easily missed. ;)

Apart from dark specimens it seems the distance between the eyes is also important, which is the point Gerrard was making.

This is the 'normal' female I posted..

Posted by blowave on 29-11-2011 22:40
#12

The one which looks like an intersex..

Posted by bonitin on 29-11-2011 23:32
#13

Thank you Ectemnius and Janet!

I do think that the abdomen on mine looks a bit strange, Ectemnius, with these 'bumps' for a female..

Another interesting question, can intersex species reproduce?;)

Some crops of the head and the abdomen that might help..

Posted by bonitin on 29-11-2011 23:33
#14

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Posted by bonitin on 29-11-2011 23:35
#15

I think the distance between the eyes is a bit less than on Janet's picture of a normal female..?

Posted by Ectemnius on 13-01-2015 17:11
#16

Hello bonitin,

I am now convinced, this is an intersex specimen of E. balteatus and presumably they are unable to reproduce.

Greetings,

Ectemnius