Mummified fifth instar -- what killed it?

[skates4marty]

A fifth instar started to look funny, so I separated it. It stopped eating and died. I put it in a container to see if any maggots came out. None did. The body stiffened in position. A perfect mummy, as though it were still eating. I haven't seen this before. Any ideas what killed it? I have had my first case of what I think is polyhedrosis "melt" this year, as have other "Monarchists" in my area. I have had tachinid flies before. I don't think I've had OE.

[skates4marty]

Hi Folks. There is some white mold on the feet and mouth parts of my mummy. So I'm thinking... Beauveria bassiana. I found it on www.monarchparasites.org (though they spell it "Beauvaria" there). And this from U of Wisc Dept of Entomology: "The very distinctive and noticeable white mummies of affected caterpillars..."

[Mona Miller]

Looks like it occurs naturally, but is also a bio-control agent.
http://www.pubmedcentral.nih.gov/articl ... tid=546202

[skates4marty]

I put the mummy in a covered container (and put it outside) to see what would happen. The fungus grew until the body was 90% covered with white. Found this info: "Beauveria bassiana is a ubiquitous soil fungus with a demonstrated ability to grow into a soft contact lens matrix. ... Our results showed that hydrogen peroxide and heat disinfection were much more effective against Beauveria bassiana than Opti-Free or ReNu." (Richardson, et al., Indiana University School of Optometry, PMID: 8454840)