Thread subject: Diptera.info :: Gymnosoma

Posted by Juergen Peters on 26-09-2006 18:56
#1
Hello!

Does this pic show enough details to tell the species? Taken on Sep-24 in Ostwestfalen/Germany. Thanks in advance!

Posted by Zeegers on 27-09-2006 21:58
#2
Well, it's a male.
Either rotundatum or nudifrons, not sure


Theo

Posted by Stephen on 27-09-2006 22:34
#3
Theo, how do you tell it is a male from the photo? The eyes would be smaller if it were a female?

Posted by Juergen Peters on 28-09-2006 01:33
#4
Hello, Theo!

Either rotundatum or nudifrons, not sure


Thanks! Since weeks I'm trying to take good enough pics to make exactly that decision ;-). Would it be possible with a better photo?

Stephen wrote:
Theo, how do you tell it is a male from the photo? The eyes would be smaller if it were a female?


I don't know if it is a valid criterion, but every time when I was sure about the sex (when seeing a mating couple), the females turned out to have less distinctive spots on the abdomen. Not exactly round, more floating together:

insektenfotos.de/Gymnosoma%20nudifrons%20(Baumwanzenfliege),%20Weibchen_007.jpg

Posted by Zeegers on 28-09-2006 21:41
#5
Well the second one is a female.
Don't look at the abdomen, look at the thorax.
Thorax is strongly golden dusted in front of suture in male,
and (nearly) completely black in female.
Very simple (and only correct in genus Gymnosoma !!!)
Well illustrated by the two pictures


Theo