Posted by Juergen Peters on 12-10-2009 00:31
#1
Hello!
Two
Medetera (Dolichopodidae) from last friday (northwest Germany). The first one from our house was relatively large, about 4 mm. The second one from an ash at forest edge measured only about 2.5 mm.
Posted by Marc Pollet on 22-10-2009 23:09
#3
Dear Jürgen,
Well, you might be aware or not, but Medetera is one of the most difficult dolichopodid genera to identify. A lot of the species even have to be dissected (at least the hypopygium) to reveal their true identity, so it's not very easy to put a name of your specimens.
What I am sure of is that both belong to the Medetera truncorum species group (with 4 strong dc). The specimen in the first picture might be either M. truncorum (with small hypopygium) or M. saxatilis (with stout hypopygium), based on the wing venation.
The specimen in the second picture is somewhat more tricky because of the pale tibiae, which reminds me of M. veles, a species that is originally Nearctic but seems to spread throughout Europe very recently. But this is just a guess and definitely not a certainty.
It would be worthwhile, though, to collect any further specimens for a thorough examination as M. veles has not been recorded from Germany yet (see Fauna Europaea for maps).
Cheers,
Marc
dr Marc Pollet (marc.pollet@inbo.be)
Posted by Juergen Peters on 23-10-2009 00:21
#4
Hello, Marc!
Many thanks for your explanations!
Yes, I know
Medetera is normally not identifiable from a photo (and these are also not the best pics...). But in the past there have been some cases here, were at least a group of species could be named (after size, season, wing venation or other characters). I am only a photo enthusiat in insects (not only Diptera) and do not collect specimens (then I would have to become more restricted to one group of interest, which I would find a pity). But I am always happy, if the range of possible species can be lowered down a little bit. If you don't try, you'll never know... ;)