Posted by Sundew on 06-08-2009 23:34
#1
Hi,
Yesterday I watched this little couple in an area very rich in
Centaurea stoebe.
C. jacea is much rarer. The flies showed no preference at that time, as they fed (at least the female) on
Achillea millefolium. I know from Valery that it is difficult to discriminate between
Ch. acrolophi and
Ch. jaceae. How certain is
Ch. acrolophi in this case?
Many thanks, Sundew
Posted by Nosferatumyia on 07-08-2009 08:30
#3
With certainty, I only could tell females of both species from measurements of the ovipositor blade (aculeus). However, there are some unexpressible differences in the wing crossbands (more or less oblique) showing that this is
acrolophi, indeed. But since there was
Acinia corniculata in the meadow, both
acrolophi and
jaceae might occur in there.
Edited by Nosferatumyia on 07-08-2009 08:31