Thread subject: Diptera.info :: I dare it again: Gymnosoma...
#1
Hello!
Is it possible to tell the species (group)? Or at least, what species it can't be...?

Photo taken two days ago, Ostwestfalen/Germany. Thanks in advance!
Larger picture:
http://www.foto-u..._W_big.jpg
Posted by
ChrisR on 27-07-2007 20:34
#2
I doubt it ... looks like a female
Gymnosoma sp. 
Would be easier with a specimen and I'd be happy to try to key anything if you could catch it and send it here

#3
Hello, Chris!
Chris Raper wrote:
I doubt it ... looks like a female
Gymnosoma sp. 
Thanks! I suspected it...
Would be easier with a specimen and I'd be happy to try to key anything if you could catch it and send it here

Many thanks for the offer, but for now I'm only photographing the insects without catching them.
Posted by
Zeegers on 28-07-2007 09:26
#4
Well. little doubt this is a female G. rotundatum.
Theo
Posted by
ChrisR on 28-07-2007 11:24
#5
Can you tell us why?

Which features work as a 'rule of thumb'?
Posted by
Zeegers on 28-07-2007 12:05
#6
-> No dusting on scutellum at all -> either rotundatum of nudifrons
-> female
-> black on parafrontals reachtin only to halfway antennal base
-> no nudifrons thus rotundatum.
Theo
#7
Hello, Theo!
Zeegers wrote:
-> No dusting on scutellum at all -> either rotundatum of nudifrons
-> female
-> black on parafrontals reachtin only to halfway antennal base
-> no nudifrons thus rotundatum.
Thanks a lot! That encourages me to furthermore try to make as detailed photos of the
Gymnosomas here also in the future

.
Posted by
Zeegers on 28-07-2007 14:53
#8
by the way:
female sex is characterized by the black thoracic dorsum (without dusting).
Theo
#9
Hello, Theo!
Zeegers wrote:
by the way:
female sex is characterized by the black thoracic dorsum (without dusting).
As a rule of thumb I had concluded from observations (seeing that in all mating couples) that the males are the ones with smaller, round, separate spots on the abdomen. (Pics below from same location and time as the above females.)
http://insektenfo...ntid=20364
Posted by
Zeegers on 28-07-2007 15:44
#10
To illustrate my point
-1) this is a male (size of spots less reliable)
-2) def. NOT nudifrons/rotundatum, most likely dolycoridis
Theo
#11
Hello, Theo!
Zeegers wrote:
To illustrate my point
-1) this is a male (size of spots less reliable)
But more easy to see even from a bigger distance ;-).
-2) def. NOT nudifrons/rotundatum, most likely dolycoridis
Interesting! Males of another species among the females of
rotundatum on the same plant stock.