Hedychrum from Belgium

[David D]

Hello,

Yesterday I found some chrysidids within a Cerceris arenaria colony. After some research I think it should be Hedychrum nobile or H. niemelai. However, I can't find what the differences are to distinguish both species. So it would be great if someone could help me with that.

David

[Euchroeus]

Hi David

nice pictures!
But we cannot ID for sure your female specimens by photos.
The only way is that you collect more female specimens and examine the shape of the last sternite.

Often H. nobile and H. niemelai fly together in the same site. Therefore you should collect more specimens.

In my experience, the larger specimens are always only H. nobile, whereas the smaller are H. niemelai. Intermediate specimens must be checked. However, once you have experience you can ID them because the fly somehow in a different way on the ground.

Cheers
Paolo

[David D]

Hi Paolo, thanks for the reply! I am currently doing an inventory of wild bees in function of a municipality project. While doing that I try to learn as much as other specimens too, especially wasps. As I already thought in the field that it would be impossible to identify the specimen on picture, I collected 1 specimen. So, I am able to check the characteristics. Only problem...I don't have an identification key for this group. Is there any on the internet that you can recommend?

Thanks!
David

[Euchroeus]

Hi David,

you can download this volume, Morgan (1984):

http://www.royensoc.co.uk/sites/default ... Part05.pdf

but in UK there are only few species.
For nobile-niemelai identification you can check this post:

viewtopic.php?f=8&t=1597&p=2484&hilit=nobile#p2484

Check the shape of the last sternite, in ventral view; the apex is differently shaped: in H. nobile is enlarged and without sulcus.

Other SEM pictures, but no keys, are availble here: http://www.researchgate.net/profile/Paolo_Rosa2
(I Crisidi della Valle d'Aosta).

Cheers
Paolo

[David D]

Thanks a lot! I will check that!

Best regards
David