The Great Awakening

Female Regal Fritillary
Photo: Ron Panzer

We have been working with Regal Fritillary conservation for several years now. This beautiful butterfly, about the size of a monarch, is in deep trouble over the eastern 2/3 of it's range (which runs from eastern Colorado and Nebraska all the way to the east coast. They are listed as a Threatened or Endangered species by most states east of the Mississippi river, including Illinois where they are Threatened. We have had some success in establishing it near Markham, southwest of Chicago. For that project, we released newborn caterpillars.

One challenge to working with regals is their life history. The adults begin flying in late June. In late July, they estivate for about a month. Only when they emerge from their midsummer nap do the females begin laying eggs- usually in the last week in August into September. The eggs hattch in late September, at which time the caterpillars eat their eggshells and immediately go into hibernation. This means that in order to raise regals in the lab, we need to do something to carry fragile, tiny larvae over the winter.

We have struggled a lot with this process. Early on, we lost hundreds of caterpillars to a bacterial outbreak. Since then, we have developed much better protocols for lab hygiene, and have gotten much better about raising all kinds of caterpillars.

Last year, we tried to carry our regals over the winter in special cages stored in a refrigerator. Periodically during the winter we would wake them up and give them a drink of water. Although we were experiencing a lot of death over the winter, it looked like we would have enough survivors to move forward. Unfortunately, what had started out as a gradual but steady decline over most of the winter accelerated rapidly over the last two weeks of March, and we had a 0% survival rate.

This year, we tried something different and put them in covered cages outside on the Museum roof. Our goal was to give them the full impact of winter cold. It worked!

Spring has been progressing nicely in Chicago. There are lots of violets (the caterpillar food plant) in bloom around the region, so yesterday we began to wake the caterpillars up. We removed them from the rooftop cages and placed them on bits of wet filter paper for a drink. Not unexpectedly, we had quite a bit of mortality. Some cages contained nothing but dead caterpillars.

Dead Regal Fritillary Larvae

Other cages ahoowed much more hopeful signs. We recovered just under 250 regal fritillary larvae that were still active and moving. After a quick drink, they were moved onto violet leaves.

Regal Fritillary Larve on wet filter paper
The green bits are frass (caterpillar poop), which indicates that they are feeding

Regal Fritillary larvae chow down on a violet leaf

The larvae are currently on violet leaves with wet filter paper in petri dishes. Over the next couple of days, we will move them to individual paper cups, where it will be easier to keep them clean. With good care, we hope to have adults in June. We will release them at the Indian Boudary Prairies southwest of Chicago.

Bins of petri dishes with regal fritillary caterpillars

And thus begins the 2010 butterfly conservation season.