Monarch Caterpillar Disaster

I put this in my response to Valerie, but I thought I would post it as well.  We just had a strange occurrence happen that we’ve never experienced before, at least not at this high of ratio.

Leecy and I took in about 7 Monarch Caterpillars about a week ago.  Only 2 of them made it to Chrysalis, the rest of them are just “dangling” straight down (not in a “J” shape).  I don’t know if they had OE disease or perhaps were attacked by the Tachinid Fly, or maybe something else.

UPDATE:  It’s probably from the Tachinid Fly.  See this link for the gory details (the fly larvae eat the Caterpillars from the inside out).

For folks who just recently started reading my blog, I have posted about parasites and diseases in Monarchs in earlier postings.  Besides the information that I posted previously, Valerie also has an excellent site about Monarch Butterflies and their diseases and parasites and goes into much more detail than I have.  If you’re curious about raising Monarch Butterflies (and the hazards that can occur), I would definitely recommend checking out her site as well.  You can find it at Evanson Art & Design.

I just took some pictures of what I was talking about above.  First, are the dead Monarch Caterpillars.  I’m pretty sure it’s because of the Tachinid Fly.  If you look closely at the images you can see that white string coming out the Caterpillars.  The Caterpillar on the far left is starting to liquefy.

Monarch Caterpillar Disaster

This image shows those “strings” protruding from the Caterpillars.  You can also see that the Chrysalis is starting to have problems as well.

Caterpillar Carnage

Here’s a closeup of the Chrysalis from the photo above.  It’s turning brown after one day, which is not a good sign.  You can also see a “string” from this Chrysalis as well.

I ended up destroying (if they weren’t dead already) all the Caterpillars and Chrysalis from these images (tossed in a ziploc baggie, thrown in the freezer).

Closeup Of Monarch Chrysalis Parasite