Thread subject: Diptera.info :: Acidia cognata
Posted by Philippe moniotte on 03-09-2007 11:36
#1
hello all,
Here is a question for the cognoscenti : when you search the web for images of Acidia cognata, you find several pictures of an essentially black fly, with heavily marked wings.
On the DI gallery, however, the two available pictures show an orange fly, with only modest markings on the wings.
Now, while looking for things to pixelise in the field the other day, i found both types (separately) on Tussilago. I saw several individuals of each type, and there appear to be also a size difference, the orange ones being slightly larger than the black ones.
Is it sex difference ? variations ? two species ?
I can post phtos later on if need be.
Cheers
Philippe
Posted by John Smit on 03-09-2007 12:49
#2
Hee Philippe,
Photo's would be much easier.
But nevertheless I can give you some kind of answer.
Acidia cognata is a rather large orange-brown species with, as you say, modest markings on the wings, mainly slender orange-brown-yellow bands.
The black specimens you found on the internet, can'd be A. cognata, I presume it's Euleia heraclei, also a leafmining species that can be found resting on leaves of Tussilago, but won't mine these leafs!
Of this latter species there are two forms, dark and orange-brown, similar wingpattern, only different colour. See also http://www.diptera.info/forum/viewthread.php?forum_id=5&thread_id=8230
Best wishes,
John
Posted by Philippe moniotte on 03-09-2007 17:11
#3
Hi John
Thanks for your reply. Here are the pictures : first the black ones
Posted by Philippe moniotte on 03-09-2007 17:16
#4
Then the orange ones.
Both pictures August 30th 2007, Marche-les-Dames, Belgium.
Posted by John Smit on 04-09-2007 08:32
#5
Hi Philippe,
It's always different from what you think based upon a description!
The first photo is Philophylla caesio, another leafminer of all kinds of Apiaceae. The second one is indeed Acidia cognata, mining in Petasites.
John
Posted by Philippe moniotte on 04-09-2007 09:08
#6
Thanks indeed John.
After your first reply and looking closer to my pix, I really started to doubt it was the same species anyway.
But it seems that the error on several website and in my one book on flies is widespread : A. cognata is pictured as something very much like Philophylla ! I guess they probably copy and propagate the mistake from one source to the other - as I was ready to do without your help !
Cheers
Philippe