Thread subject: Diptera.info :: Parasitic wasp, of holly leaf-miner?

Posted by John Bratton on 27-02-2010 18:42
#1

I swept this tiny parasitica, 2.2 mm long, from a holly bush infested with holly leaf-miner Phytomyza ilicis. Does anyone know if it could be a parasite of this fly, please? It is from Bangor, North Wales, 24 Feb. 2010.

The dark patch in the wing is a genuine wing marking, not out-of-focus dirt.

It is photographed in alcohol by the high-tech method of holding my camera against the microscope eyepiece.

John

Edited by John Bratton on 27-02-2010 18:49

Posted by Paul Beuk on 27-02-2010 21:04
#2

Eulophidae

Posted by John Bratton on 01-03-2010 16:26
#3

Thanks for this. I probably won't get any further than family, but I'll keep the specimen. One day I might meet a eulophid specialist.

Posted by empeejay on 02-03-2010 22:44
#4

Chrysocharis gemma looks like it might be distinct possibility, especially considering the association with Phytomyza ilicis.

Posted by John Bratton on 03-03-2010 14:07
#5

Thanks very much. Do you know what the critical features are that I should look for on the specimen, please?

John

Posted by empeejay on 03-03-2010 23:31
#6

The following characters should be sufficient to separate this species from other British Eulophidae: -

Forewing submarginal vein with 2 dorsal bristles.
Scutellum with only 2 bristles situated near the middle.
Forewing postmarginal vein 2 x longer than stigmal vein.
Pronotal collar with a sharp transverse carina and with hind margin smooth and shining.
Propodeal callus with 7-10 setae.
Forewing usually with a single large fuscous discal cloud.

According to Hansson in his 1985 revision of Palearctic Chrysocharis it is a "Solitary endoparasite of leafminers mining leaves which are tough and leathery.
Plants with tough and leathery leaves are frequently evergreens, and it is interesting to note that C. gemma overwinters in the adult stage and seems to be more or less active even during the winter".

Hope this helps.

Posted by John Bratton on 05-03-2010 18:16
#7

Thanks for these characters. I've checked them all except the setae on the propodeal callus. I don't know whether they are absent, or I just can't see them.

Thanks for your help,
John

Posted by John Bratton on 10-03-2010 14:06
#8

Ian McLean has kindly sent me a copy of Hansson's key. I've managed to see the setae on the propodeal callus and the ornamentation fits Hansson's fig. 112, so I've convinced myself it is Chrysocharis gemma.