I had one that made a cocoon but it looks small and just odd. I'm also finding lots of cats that tried to make their cocoons but ended up kind of going limp and dying. There is also a white thread looking thing coming out of the dead caterpillars. Seems like I remember reading something about the thread and it is some kind of parasite? Is there anything I can do to protect the caterpillars that are left?
I found this. Poor things.
http://www.uga.edu/monarchparasites/parasites_in_monarchs/index.html
Unfortunately there will be predators. You could put the caterpilllars into a cage and raise them inside...but they could already have been zapped. A caterpillar will continue to eat and even pupate - basically it's a zombie serving as a living host. Most times it won't have any obvious signs (like all those cocoons on the sphinx caterpillar in the link you provided) until the pesky fly or wasp emerges. However, sometimes you can see a small dark spot on some caterpillars where they've been stung by the egg laying wasp or fly. Same goes for chrysalids.
Here's a Bordered Patch chrysalis that's been parasitized. Note the small dark spot the red arrow is pointing to.
pestee.... The earlier you can collect and cage raise the caterpillars the better chance they have of survival. What you are looking at is more than likely the Tachinid fly as in the info you posted. When they look like your photo the quicker you destroy the caterpillar the less likely the parasites will emerge. That is our only defense to cut down the cycle. If you spray your garden for them you kill beneficial insects and also the butterflies.
If you are interested in raising the caterpillars.....look at the sticky on the top of the Hummingbird and Butterfly forum. It has loads of helpful info.
http://davesgarden.com/community/forums/t/744103/
This message was edited Sep 27, 2010 9:33 PM
