Posted by Simon Thevenin on 08-12-2020 18:06
#1
Hello,
I found hundreds of those flies while cutting oaks in South of France (13). Those Cecidomyiids were only 2-4 mm long, ovipositing at oak. Is this Xylodiplosis ?
Here is a video link of the oviposition :
https://www.youtube.com/watch?v=NHz6rGdXSZk
Edited by Simon Thevenin on 08-12-2020 18:09
Posted by John Carr on 09-12-2020 19:28
#5
Simon Thevenin wrote:
I also have top photos with the wing venation, if needed
I wouldn't be able to identify with confidence. Gagné's (2018) key to North American Cecidomyiinae mentions fresh-cut logs as habitat for only two genera:
Xylodiplosis and
Trogodiplosis. To separate them using the key requires a good look at male genitalia or female mouthparts.
Here is Gagné's (1985) generic diagnosis for
Xylodiplosis: "Eyes very extensive, about 15 facets long at vertex. Postvertical peak long, narrow. Male flagellomeres regular, binodal, tricircumfilar. Female flagellomeres cylindrical, regular. Wing with long, curved R5. Tarsal claws simple, bent near basal third. Male genitalia: cerci convex, short; hypoproct concave posteriorly; aedeagus short, pointed, and gonocoxites unlobed. Ovipositor long, protrusible. the cerci short, ovoid, separate."
...and for
Trogodiplosis: "Eyes very extensive, about 17 facets long at vertex. Postocciput very narrow, terminating in long dorsal peak with 2 long setae. Male antennal flagellomeres binodal, tricircumfilar. Mouthparts sexually dimorphic, in male unmodified from usual plan of supertribe, in female larger, more inflated than in male, the hypopharynx lined laterally with large, wide teeth instead of more usual, long setulae. Palpus 4-segmented. Thorax: Wing with long, curved R5, weak M3+4, without evident Rs. Legs long. Tarsal claws robust, bent near basal third, untoothed."
Posted by John Carr on 09-12-2020 19:29
#6
According to the catalog,
Trogodiplosis is not known from Europe (only Russian Far East and North America), so based on habitat
Xylodiplosis is very likely.