Gossamer Tapestry

Reflections on conservation, butterflies, and ecology in the nation's heartland

Saturday, May 09, 2009

Gorgone Checkerspots Break Diapause

Gorgone Checkerspot (Chlosyne gorgone)
Image from wisconsinbutterflies.org

Gorgone Checkerspots are rare in northern Illinois. Years ago, my very first experience with butterfly translocation was to help Ron Panzer try to establish a population at Nachusa Grasslands. Last summer, we began a project to attempt breeding this species in the lab. We obtained a gravid female from a railroad prairie in Grundy County, and got dozens of eggs from her. About half of the larvae went on to complete their life cycle. The other half went into diapause (a general cessation of activity) sometime in August.

Larva Land - Wintering Cages at the Portland Zoo

In September, Vincent and I visited the Portland Zoo to learn techniques for holding larvae over the winter. It's a process we continue to struggle with. They were using a technique where caterpillars are placed in yogurt cups and stored outdoors under inverted terracotta flower pots for the winter. They were having success with a close relative of the Gorgone Checkerspot, so we decided to give their technique a try.

All winter long, our Gorgone larvae have been under flower pots on the museum roof. Last week, we realized that their host plants had sprouted sufficiently for us to try waking them up. We put them in caterpillar rearing cages with purple coneflower leaves. For several days, not much happened. On Thursday, I suggested that Vincent move a couple of the cages into direct sunlight. Several of the caterpillars promptly molted. On Friday, everyone went into the sun.

Gorgone Checkerspot larvae on Purple Coneflower leaves (5/9/09)

Today, all of the surviving larvae have molted and begun feeding. You can see all the frass (insect poo) and a shed skin on the bottom of the cup in the photo above. I had no idea that molting would be the first step that would happen when the larvae broke diapause. A brief shot of direct sunlight seems to be essential in the process. About half of the larvae that we placed outside survived the winter (that's reasonably good, especially for a first try). We will repeat the experiment on a larger scale this year. There are several hill prairies in northeastern Illinois that could soon be home to new populations of this lovely species.

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At 15:55, Anonymous Anonymous said...

Nice metalmarks! Hope you can spread them back to their former range.

At 18:11, Anonymous Anonymous said...

Wonderful to see.

At 19:09, Blogger Will said...

I love the striped antennae. Knowing you, I simply assume you're not releasing any species you're trying to revive into an environment where they'll upset things. But if they've become reduced in numbers to a significant degree for some time, won't the balance have shifted to a point where re-introduction WOULD be an upset?

At 23:00, Blogger Gallicissa said...

Very clever experiment. It's amazing what magic the sun can do.

Gorgone Checker spot is gorgeous.

And I learnt a new word for scrabble - frass, thanks!

At 12:59, Blogger Doug Taron said...

Anon and lilian- Thanks. It will be interesting to see where this goes.

Will- I like the striped antennea, too. Short answer to your question: we are very careful about appropriate site selection for this kind of work. Longer answer: That's such a good question that it's worthy of its own blog post. I'll try to get something out about it.

Amila- Are you a Scrabble fan? Do you ever play the online Facebook version of Scrabble? If you do, I want to challenger you.

At 03:24, Blogger Kathiesbirds said...

Wow Doug, that's awesome! I was wondering about the black specs in the bottom of the cup. I'm glad you told us!

Sure missed you in WV. You would have loved it. I thought of you everytime we saw a butterfly or an insect. I don't know when we will do it again but I hope you can join us next time! TR is a hoot!

At 00:12, Blogger Gallicissa said...

Yes I am a big time Scrabble fan. I am not on Facebook (which is a deliberate attempt to reduce computer time). I'd love to play a game with you one day though.


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