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Photo#1163152
Pteromalus wasps emerge from a monarch chrysalis - Pteromalus

Pteromalus wasps emerge from a monarch chrysalis - Pteromalus
La Crosse County, Wisconsin, USA
November 5, 2015
When packing up for a short paddling trip 9/12/15 I noticed a monarch chrysalis on the side of my canoe. I carefully removed it and using masking tape attached it to a wire suspended from my house. Weeks passed and other monarchs matured and emerged but this chrysalis turned very dark, then faded to tan. I eventually brought it inside where it hung on my refrigerator. To my surprise I noticed dozens if not hundreds of tiny wasps emerging today. While heading out the door I popped the chrysalis into a glass tube to photograph at work. During my 30 minute drive another 20-30 wasps emerged.

I forwarded these photos to the Monarch Joint Venture at UMN and Carl Stenoin was kind enough to reply: "These are probably Pteromalus cassotis, but I can't be 100% sure without seeing them under a microscope..."
Carl Stenoien - PhD Candidate, Ecology, Evolution, Behavior Program
Graduate Research Fellow, The Monarch Lab - University of Minnesota

Images of this individual: tag all
Pteromalus wasps emerge from a monarch chrysalis - Pteromalus Pteromalus wasps emerge from a monarch chrysalis - Pteromalus Pteromalus wasps emerge from a monarch chrysalis - Pteromalus

Moved
Moved from ID Request.
Moving here for now. Did you get a confirmation? Should I create a species page and move it there? Please let me know.
Great find!

Pteromalus cassotis
P. puparum was mis-identified. Are you sending these to the Oberhauser Lab in St. Paul? Carl Stenoien and Karen Oberhauser are working with these wasps there.

 
Yes
Thanks for correcting - see second paragraph above:

 
Awesome!
I got excited for another documentation of this species. Carl and I have been trying to find the range of this parasitoid. Would you be willing to email me the coordinates of where you collected these from for our records? mccoshsm@gmail.com

Nice, Dan…
I would also agree that this likely to be P. cassotis, based on the gregarious nature of this species where 200 or more adults may emege from a single pupa. The literature suggests that P. puparium will also occasionally parasitize Monarch pupae, but that they often fail to develop into adults. If you receive confirmation of the species, pls let us know, and we can create a species page for it here on BG.

See reference here.

 
Thanks
Thank you - I am mailing samples for verification. I'll let you know what I find out!

 
Absolutely neat.
Absolutely neat.

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