Diptera.info

Posted by ChrisR on 01-12-2007 18:39

The recent influx of neotropical photos in the Diptera side prompted me to dig out these photos of a sphecid(?) which seems to be mimicing a Pepsis wasp - but I'm not sure if my indentifications are even close - or why it might want to look like a Pepsis. Location: French Guyana.

Edited by ChrisR on 02-12-2007 17:38

Posted by jorgemotalmeida on 01-12-2007 18:44

big and spectacular insects.

the last one I leave that for fun.

I know what it is ... and when you know about the right family you will be baffled! I'm sure!

Posted by ChrisR on 01-12-2007 19:10

Another specimen at a different angle...
(and yes, I will side-pin anything

- note the steep angle of the pin to avoid damaging the same surface on the other side)

Edited by ChrisR on 01-12-2007 19:12

Posted by Christian Schmid-Egger on 01-12-2007 22:30

From general aspects, the specid wasp looks like a member of the genus Chlorion (Family Sphecidae s.str.), but some details in the wing venation are different. Because I don't now the neotropical fauna so well, I cannot say more about the genus. In any case, it is a genus close to Sphex.
The Pepsis is correct, and a species ID is not possbible by photo.

The question of mimicry is interesting, because both species can sting and defend themselves. So the question is which one will imitate the other one.

Regards, Christian

Posted by ChrisR on 02-12-2007 00:40

Thanks Christian - glad I wasn't too far by saying 'sphecidae'

The mimicry thing puzzled me too - unless it it just M?llerian mimicry in action ... two harmful species evolving towards a common, shared pattern that all predators understand.

Do you know how Pepsis spp. can be identified to species? Last time I investigated I was told they were nearly impossible

I have a lot of different pompylid wasps here from French Guyana and it would be nice to get some kind of name for them. Most are very different from normal "Pepsis" (see below):

Posted by ChrisR on 02-12-2007 00:48

#16

and another really amazing sphecid

(sorry, last one)

It was a pretty good holiday but tachinids were very short on the ground so I had to concentrate on Hymenoptera. I only got stung once, by a social wasp, so I probably got off lightly considering how bad pompylid stings are supposed to be

Edited by ChrisR on 02-12-2007 00:51

Posted by Christian Schmid-Egger on 02-12-2007 09:01

#17

Very nice specimens, and no problem with the quantity, I can look for more :-)

The first Pompilid is not Pepsis (with the white, apical wing spots), the others most probable are Pepsis or the related Entypus. Specimens with strong, straight antennae are males. Nice colores, I like these neotropical species a lot. In 1987 I collected in Brasil, and also found similiar stuff.

About identification: I know two specialists: Colin Vardy in London is revising Pepsis, and Raymond Wahis in Liege/Belgium is identifying all other genera in South America. Please, send me an Email, and I give the contact data. (christian at bembix.de).

The last specimen is a Sceliphron (Sphecidae s.str.). Normally, species ID is possible, there is a recent world revision.

Regards, Christian

Posted by ChrisR on 02-12-2007 14:48

#18

Many thanks for the advice - email sent

I have studdied pompilids here in the UK so collecting them in the neotropics was a fairly high priority for me. I knew it would be very hard to identify them but just the chance to bring back specimens from this relatively under-collected country was too important to miss.

The sphecids were more difficult to find but I have a few of these black & yellow ones and they were some of my favourites.

I will post some more images later, if no-one objects

Edit: I have had a quick look at Sceliphron in Google and I agree they look very close. The fact that they are mud-daubers is also significant because my specimens were mainly collected as they came in to collect mud around shallow puddles on roads

Edited by ChrisR on 02-12-2007 14:51

Posted by Christian Schmid-Egger on 02-12-2007 16:18

#19

There is a nice site about American Pompilids with a key to genus level. But, key is difficult, I did not succeed with some nice specimens from Chile :-(

http://www.biology.usu.edu/labsites/pompilidweb/default.htm

More later and by Email,
Regards, Christian

Posted by Kahis on 02-12-2007 16:21

#20

Chris Raper wrote:
I probably got off lightly considering how bad pompylid stings are supposed to be

I got stung by an European one, a small one. It was bad enough. Owie owww! Fortunately the blinding pain lasted only for 5 seconds or so. Can't image what a bigger dose of the same medicine would do. I'd rather be kicked in the family jewels