Thread subject: Diptera.info :: I dare it again: Gymnosoma...

Posted by Juergen Peters on 27-07-2007 20:00
#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

Edited by Juergen Peters on 27-07-2007 20:01

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 :D

Posted by Juergen Peters on 27-07-2007 21:09
#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 :D


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? :D 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

Posted by Juergen Peters on 28-07-2007 14:46
#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

Posted by Juergen Peters on 28-07-2007 15:21
#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

Posted by Juergen Peters on 28-07-2007 16:25
#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.