Diptera.info

Posted by jorgemotalmeida on 15-06-2007 19:42

Hi

* locality - Silgueiros - Viseu - PORTUGAL
* date - 2007.06.15
* size - 7 mm (medium fly)
* habitat - openland, near river - near Quercus sp. above dry and burnt (?) Rubus sp.
* substrate - hovering with other acrocerid.

This fly was an amazing thing to see!!! It is breathtaking to see this fly at the first time. In dorsal view... we cannot see the head. :o It has a proboscis among the legs! All proboscis is yellow but at the extremity is a little dark. Legs are not totally yellow.

Third segment in antenna very short with apical hair , so Cyrtinae. Inside this we have 5 possible genus:
Cyrtus, Opsebius, Paracrocera, Acrocera y Ogcodes -- the last is totally black. The others have small proboscis, but Cyrtus has long proboscis as you can see. So probably Cyrtus. There is Cyrtus gibbus for Portugal, but the legs ARE NOT totally yellow. Neither can be C. pusillus because probosci is not totally black. My spanish friend Gallego helped me with biblio but we don?t have the descriptions for other possible species...

One thing is sure: this fly amazes me totally!! :D

EDIT ---> Title changed from "the most crazy fly I've seen so far! Acroceridae - Cyrtus sp. which one??" to "the most crazy fly I've seen so far! Acroceridae - Cyrtus gibbus"

Edited by jorgemotalmeida on 20-06-2007 09:04

Posted by jorgemotalmeida on 15-06-2007 19:46

it looks like a wasp!! ;)
This fly is spiders' parasitoid. Under flies I spotted Thanatus cf. vulgaris/atratus (Philodromidae) , and some Pardosa sp. and Hogna radiata (both Lycosidae) wandering around.
But it seems that acrocerids.. "apparently have no fixed host-parasitoid relationships at the species level". And attacks spiders that make web? (not sure about this. But lycosids and philodromids don?t build web. )

Edited by jorgemotalmeida on 15-06-2007 20:13

Posted by jorgemotalmeida on 15-06-2007 23:57

#14

I found this fly in this zone: http://tinyurl.com/227zf6 (near that rectangular building, about 20 m to the right - not in the shadow zone neither under the dense trees).

I testify the beginning of mating dance: the flies were flying up and down very quick. The distinctive colours, and the peculiar flight... called me :)

Thank you all!

Posted by jorgemotalmeida on 16-06-2007 09:15

#15

according to Tony Irwin, in dipterist's handbook, it seems that all acrocerids were reared from lycosids spiders.

The way that larva reaches the spiders is curious. The adults put eggs on the ground and when they mature, the larva can jump :o and seek for spiders - and enters in joints... and then go to the abdomen. In IV instar stage... they ate all spider... :|

Posted by Tony Irwin on 16-06-2007 16:46

#16

jorgemotalmeida wrote:
according to Tony Irwin, in dipterist's handbook, it seems that all acrocerids were reared from lycosids spiders.

The Dipterists Handbook was written 30 years ago - I'm not sure whether more recent rearing records of (British) acrocerids include other families of spiders. Certainly other families are involved in North America.
The Amateur Entomologists' Society has plans to revise the Dipterists Handbook, and publish a completely new edition. Although aimed primarily at British Dipterists, there will be plenty of useful up-to-date information for everyone when it appears. :)

Posted by Tony Irwin on 16-06-2007 21:05

#18

jorgemotalmeida wrote:
great news! and when will be ready the new edition? :)

I'm not sure. The new edition will be like the last one - there will be quite a number of people involved in writing it, and the process of getting the new (or old! :p) authors together has only just started. I guess it will be at least a year before it's available - most of the authors are likely to be busy with other things over the summer.
I'll try to keep everyone posted on progress.

Posted by jorgemotalmeida on 20-06-2007 09:05

#20

Paul Beuk wrote:
I have seen nothing in these pictures that is in contradiction with Cyrtus gibbus as described in Die Fliegen der palaearktischen Region by Sack (1936).

:) And it was spotted here before.
Anyway one of the most interesting flies I've ever seen since Myopa picta. :)

Is there any information about the size of planidium for these flies?? Any scheme how it seems?
I didn?t know that "They are cosmopolitan in distribution but rarely observed in most places; the majority of the over 500 species are known from fewer than 10 specimens." in wikipedia.org . It lacks there a link for diptera gallery. :D

Edited by jorgemotalmeida on 20-06-2007 10:43

Posted by Kahis on 20-06-2007 14:28

#22

Tony Irwin wrote:
The Dipterists Handbook was written 30 years ago - I'm not sure whether more recent rearing records of (British) acrocerids include other families of spiders. Certainly other families are involved in North America.
The Amateur Entomologists' Society has plans to revise the Dipterists Handbook, and publish a completely new edition. Although aimed primarily at British Dipterists, there will be plenty of useful up-to-date information for everyone when it appears. :)

Ooh, what excellent news! Please please please do a updated edition of this gem of a book! I'll buy two :D I have the original and it's a perfect introduction to the wonderful (and weird) world of flies.

Posted by David Gibbs on 21-06-2007 12:03

#23

at the moment C. gibbus is the only species listed in fauna europa, the other names being synonymised after Emilia Nartshuk went through the Paris collection and labelled all specimens of Cyrtus as gibbus, hence treating all forms as one highly variable taxon. However, this has never been officially published as far as I know. The genus is being revised by Christian Kehlmaier and he thinks that there might be two species mixed up here. so the name gibbus is correct for the European list as it stands but might need to be changed depending on the outcome of his revision.

thanks to Christian for the above information.

Posted by jorgemotalmeida on 21-06-2007 16:04

#24

believe it or not... but today I .... found another acrocerid!!! :o What are the probabilities to find another acrocerid if this sentence (yes, I showed it before..) is true: "They are cosmopolitan in distribution but rarely observed in most places; the majority of the over 500 species are known from fewer than 10 specimens. They are found most commonly in semi-arid tropical locations."? :) This time was above Rubus sp. leaf. It was my third acrocerid. It is Cyrtus as well. For species... I must see better the legs and proboscis, but probably is the same species (I have collected it..). I found it in the same place and at almost same hour. About 2.30 pm with strong Sun. (finally good weather that arrived today in June solstice!).

Edited by jorgemotalmeida on 21-06-2007 16:07