Wow! How exciting, Jeff!
I don't get silvery checkerspots here, so I have no clue about how to handle them over the winter. One of my books says the cats overwinter at the base of the host plant, that's all I know.
I think Mary Ann or Bernergrrl may have overwintered checkerspot cats - hopefully, they'll see this and chime in if they have.
Sherry

Hi Jeff, I don't think I successfully overwinter Harris' Checkerspots. I think they dessicated over the winter, but once I saw the host plant beginning to emerge in the spring, I put out what I had at the base of the host plant outside. Later, I saw two caterpillars, but I am not sure if they were from the original nest or ones that I had kept over the winter.

Larry (Ladobe) (where is he these days?) mentioned that he had an overwintering set-up--cages that were for outside so that the cats could overwinter in the debris but still get the benefit of the cold/humidity of snow conditions that are typical of the cats' environment.

NABA has an article about overwintering Regal Frit caterpillars, and it was tricky because there so many difficult things--humidity, host plant issues, but they had the most success with a type of violet that wasn't fuzzy, and they also kept "waking up" the caterpillars--they kept interrupting the diapause purposely. That article could be helpful for you in figuring out what to do.

Good luck! Looking forward to hearing about your adventures.

On another note, if you keep them in a garage or something, I wonder how well the paper bag thing would work?

Since you have so many, you could perhaps play around with overwintering set-ups--it would be very valuable knowledge, I think.

Maybe Elizabeth knows of more studies about how to keep these overwintering caterpillars alive.

Here is a link that might be useful: Rearing Regal Frits

The article was fascinating. I think I have a leg up on the Regal Frits, because my cats are 2nd instar already and headed for instar 3 before hibernating. It's those first two instars that are so delicate.

I think my current leading plan is to put a box-sleeve over several plants and just turn the cats loose.

Jeff

Hi Jeff;
I was waiting for Bernergrrl to reply since I have not overwintered any cats yet. Fritilaries are really difficult and the original work involved drilling holes in wood blocks, soaking them and then putting the cats in them to overwinter. Jaret Daniels and some of the research I have read really emphasizes the importance of duff. From a federal website "Duff: Partially to fully decomposed organic material between the Litter-Lichen-Moss (LLM) stratum and mineral soil. Duff is described in two layers: an upper (Fermentation) layer and a lower (Humus) layer.
" I don't know if they use it but I assume so. One of the problems that we are having in our forests and gardens is that earthworms are destroying this layer. Yes, earthworms are not butterfly friendly. They are not even native but are escapees from Europe and Asia. So, if you put your cats outside to overwinter, make sure there is enough debris for them to bury into. Assuming this is their habit. Another thing is making sure they have time to acclimate. If they are not outside now (are in your home) I would do it as soon as possible. Many animals, from insects to frogs, require the buildup of a glycol type chemical in their blood. This can take time and probably is in response to temperature fluctuations. I would think putting them in a cage with some peat or good high organic content soil then a lot of leaves would be fine. Then put the cage out in the elements, out of the sun but so rain and snow can get to it. You don't want them to dry out. The one thing to watch for is ants. We lose a lot of exposed chrysalises to them and I assume a sluggish caterpillar would not pose a problem for them. It ain't pretty.

Here in SW Ohio I have not seen a silvery checkerspot. They should be common. I am worried about the species as a whole. I wonder if it is because they overwinter as cats. Once I read about earthworms and the damage they are doing to our forests, I can't look at them the same way :(.

Let me know how it goes. I want to try to raise this species as well,
Elisabeth

Fascinating info, Elisabeth; I always wondered how the cats were able to make it through the winter--the glycol explains it.

Sad about the earthworms...