Posted by
HTK on 23-06-2013 22:30
#1
Is this Ephemera danica or perhaps another Ephemera species (picture 1) with the corresponding exuvia (picture 2)? I would greatly appreciate your help. I found both of them in considerable numbers on the walls and windows of an old school building at Bad Münstereifel (West Germany), about 50 yards from the small river (Erft) flowing through the town, about two weeks ago.
Picture 1:
Edited by
HTK on 03-07-2013 19:12
Posted by
Sundew on 27-07-2013 13:03
#6
Dear Hans Theo, I am absolutely no Ephemeroptera expert. However, in this text about
E. danica (
http://www.epheme...o.uk/3912/) a useful description of the abdomen markings is given as well as a comparison with other species. From this comparison, I would tend to
E. danica, too, as the dark markings on the first segments are lacking.
I also have some unidentified Ephemeroptera photos in store...
Regards, Sundew
Edited by
Sundew on 27-07-2013 13:05
Posted by
HTK on 28-07-2013 10:17
#7
Hallo Sundew,
thank you (once again!) for your comments and the very useful link (you find very little on mayflies in the standard guides on insects). I have already downloaded all the pages of the UK Ephemeroptera Recording Scheme. I can't remember the source I used, but it was also the markings on the upper surface of the body that lead me to believe it was E. danica (I wasn't sure about how reliable this criterion was as I couldn't find any information on the amount of variation).
If you find the time, have a look at the exuvia (picture 2) again. As I understand it, it should be the exuvia of the subimago. For interesting pictures see www.fliegenfischer-forum.de/.../ephemera-danica-verwandlung-subimag.
By the way, the emergence of these mayflies seemed in fact to be limited to just a few weeks (in June, maybe in May before I detected them by chance). The exuviae were then swept away by heavy rainfall, and neither new exuviae nor imagos could be detected in recent weeks. Maybe I'll find the time next year to haver closer look at the pattern of emergence.
Best wishes,
Hans Theo K.