Thread subject: Diptera.info :: Scaeva sp.? => Scaeva dignota/selenitica

Posted by Christian Schulz on 29-06-2020 09:43
#1

Hi,

is it in this case possible to decide between Scaeva pyrastri and Scaeva selenitica?

Italy, Alto Adige, Meran 2000, ca. 2050 m, 02.10.2014.

Thanks a lot!
Christian

Edited by Christian Schulz on 23-08-2020 21:03

Posted by Sundew on 30-06-2020 00:57
#2

This is a tricky question! In Italy, there are 5 Scaeva species, but the key https://www.biodi...S-2014.pdf brings us to S. dignota and S. selenitica. (BTW, as to the colour of the marks there is no differention between yellow and white, the marks are called "pale" in all species.) It is said that females of the two species remain difficult to separate. Features of S. dignota seen in your picture MIGHT be a shallowly concave frons and the pale marks of tergite 3 and 4 getting very close to the lateral tergite margin (a character mentioned by van Veen but questioned by other authors). On the other hand, the hairs on the eyes seem very long for S. dignota. So we got stuck here...
Regards, Sundew

Posted by Christian Schulz on 30-06-2020 08:50
#3

Hi Sundew,
thank you very much for your detailed answer! Maybe the attached pic - slightly different from the one before and at a larger scale - can help, but having S. dignota/selenitica is more than I dared to expect. Thanks again!

Christian