Thread subject: Diptera.info :: Mystery disk with hymenoptera (= Monodontomerus)
Posted by John Carr on 17-10-2013 13:47
#1
I found this on a rock wall beside a parking lot in suburban Massachusetts, USA. It contained hymenoptera coccoons about 1 cm long and was covered in 4 mm Torymidae, probably parasitoids or hyperparasitoids. I could not get an ID on BugGuide (
http://bugguide.n...iew/192545), but there was a comment that the fibers of the white object might be synthetic. The disk was spongy, not hard.
Edited by John Carr on 27-10-2013 01:13
Posted by Steve Crellin on 18-10-2013 14:23
#2
Hi John,
I mentioned your query to a friend with an interest in these little parasitic wasps and he replied with the following:
"I fear that any attempt to name the mystery object on Diptera info would only be a guess. I thought initially it might be wool spun by parasitic larvae of the primary parasitoid that emerged from a lep larva as they formed cocoons eg. an Apanteles (Braconidae) or similar genus. Usually the outline of individual cocoons is evident so there must be a better answer. I worked a bit with phytophagous species of Torymidae in Florida and South America and doubt that this one belongs to that group of species. The best lead would probably to get the torymid identified and check what host records are known for that species."
Sadly, it doesn't provide an answer beyond those you've already received on the other forum. If you do get an answer please let me know so I can pass the news on to my friend.
Steve
Posted by empeejay on 19-10-2013 10:24
#3
The parasites are almost certainly a
Monodontomerus species but I have no idea what the disc could be. Grissell revised the New World
Monodontomerus species in 2000 and listed various hosts in Diptera, Lepidoptera and Hymenoptera.
Posted by John Carr on 19-10-2013 13:43
#4
Monodontomerus dentipes is released to control invasive Diprionidae. Maybe this disk is a release mechanism, an artificial structure to support parasitized cocoons.
Posted by John Carr on 29-10-2013 23:19
#5
Current leading theory is
Monodontomerus montivagus parasitizing
Anthidium.
Posted by empeejay on 30-10-2013 19:00
#6
Monodontomerus dentipes is decribed by Grissell as "unique in the subapical placement of the femoral tooth". I've created a crude image comparing the hind femur of your insect with that of
dentipes, which seems to suggest that it is not that species. Another feature of
dentipes is that the ovipositor is about 0.5 x length of the metasoma, which again is evidently not the case. There is no other species listed as parasitizing Diprionidae.
That probably doesn't help much but suggests you may be right in looking for an alternate host.