i had 2 chrysalis about to hatch 2 days ago and when I returned in a few hours there was 7 or 8 inch long thread like silk hanging from the bottom of the chrysalis and the butterfly never emerged. Like it was still born.I've had a few others that didn't make it past differant stages but none with the strings.What are they (strings) and what went wrong?
Don
P.S. Of about 75 I released about 65 ,is that a good mortality rate?
Still Born Monarch Chrysalis
Sounds like a Tachinid Fly, which is a parasitoid of caterpillars like Monarchs. There should be a dark capsule, which will hatch into another fly. If you haven't already, destroy it. Once a caterpillar is infected, it's doomed and there's nothing that can be done. If you collect the eggs or small caterpillars and raise them in a cage that the little flies can't enter, they will be safe from that fate. I think the flies usually infect the 3rd instar or later cats. Sorry about your two Monarchs! I've had that happen also. Really gross to see.
Thanks for the info Linda,I'll surely keep an eye out for them.
Has anyone herd of this happening before the cat pupates? I have a hanging J that never proceeded- has a silk string as previously mentioned. A brief Google revealed that the Tachinids are used as beneficial insects to control cabbage worm loopers. To attract the Tachinids, you can plant umbelliferae- parsley, dill, fennel. These are also what you plant to attract BSTs, I planted a bunch of these this year.
DH says it's not the same cause of death because ours never pupated first. I say it could happen since the cats were at least 3rd instar.
What say you?
Maggie
I just now over this past weekend had a cat go into the J form. Then went completely limp.Like it died right there.Several others have went into the J and then went to completion into the chrysalis since that one formed.I also can't figure out why.(Where's Dr. House when you need him).
Yes, Tachinid Flies are a very beneficial wasp! Please never destroy these tiny little insects.
By what I recall from reading about them & maybe PBS show, the Tachinid Fly (very tiny wasps no bigger than a small fingernail) lay a smaller than rice-sized white egg on the caterpillar that is held in place by a short, stiff, white string. After hatching, they burrow into the living caterpillar & it's dead before it even pupates.
It's unfortunate that your butterfly died before emerging but I don't think it was a Tachinid Fly that killed it.
If it is a Tachinid fly, it is not beneficial to me and is in direct opposition to the main focus of my gardening for the last two years. You bet I'll kill it if I find it.
You may be right though, the problem may not be the tachinid. I need more info. Do you have any idea what could have happened? I had 3 cats. 2 pupated but one of those looks funny. The chrysalis looks a bit dehydrated and partly discolored amber brown.
Maggie
I've had a spider inject a coccoon that was outside. I knocked the spider off and brought it in, but it was too late. It got enough poison and died.
Here are some pics. I apologize for the pics but perhaps in this instance it's best if they aren't too clear. You can see the string from the cat though.
Maggie
You can see the discoloration on the chrysalis here.
I've never seen anything like it. Hope you find out what happened. I'm curious.
Maggie,
The string appears to be the same as on mine.i wonder if the release of the string is a cat or a chrysalis last gasp of life before it dies.
Don't know. Too bad it's not lethal to the infecting parasite.
Maggie
FYI,
I posted a question to the UF Butterfly Museum staff. Maybe they can tell us.
Maggie
WooHoo! I got a very gracious response from Dr. Hay-Roe, a UF entomologist with a post-doc in lepidoptera. She's asked for a pupa sample so they can figure out if it's a pathogen or developmental issue. If nothing else, this will insure that the problem disappears.
Maggie
Wow that's great Maggie I think your really on to something.