#1
Hi !
There are several large plants of Bryonia dioica in my garden (Heron, Belgium) . There has been this year a good sized population of the tephritid
Goniglossum wiedemannii. They are now on the decline, but there is a pullulation of a small braconid (Opiinae, I think) constantly patrolling the plants.
Is there anywhere I could learn about this association, how specific it is, etc... ?
Thanks in advance for your comments
Philippe
#2
Hello Philippe, I have seen the same braconid wasp on female red bryony (Aug/Sep 2021 SE of the Netherlands) visited by G. wiedemanni earlier in the season. Some online reseach learned me that the parasitoid is probably Utetes testaceus (= Opius testaceus). With that name I have found more info, associated hosts are G. wiedemanni and probably Rhagoletis spec. and Euphranta spec.
A braconid specialist warned me not to assume this is certain 'because this is such an incredibly taxonomically difficult group'. Citing specialist D Quicke on this matter: 'They are koinobiont endoparasitoids and so might be expected to have narrow host ranges - but not necessarily so. In such groups molecular studies often reveal cryptic species so i would use the name in 'xxx' as a possible/probable identification until such time as a proper study is carried out. The main exception would be if the original description of the species was noted as being from that host. '
I started looking for the braconid after receiving pictures from a colleague who discovered the braconid (and the probable relation with G. wiedemanni) in his garden. Fascinating to see that not only specialised guests such as G. wiedemanni, A. florea and H. argus manage to find red bryony here (being quite rare in these areas), but also a parasitoid like U. testaceus!
Hoping this will help you further, best regards, Annemiek