Regal Fritillary Butterfly

The Peggy Notebaert Nature Museum of the Chicago Academy of Sciences is working to assess potential homes for the regal fritillary and develop techniques for breeding this fragile species.

Although it is not formally named the Illinois state butterfly, some might argue that the regal fritillary, with its beautiful blue-black wings and prominent white spots, is an Illinois icon. But while the species may seem abundant in the prairies of the Prairie State, its population has seen visible declines east of the Mississippi River, in part due to much of its habitat becoming replaced by shopping malls and suburban sprawl. Biologist Doug Taron and the team at the Peggy Notebaert Nature Museum seek to better understand these butterflies and their living conditions so they can help to preserve the species.

The regal fritillary has an unusual breeding pattern – its caterpillars hatch right before the cold season begins. These tiny but mighty caterpillars are built to survive the cold, but only when conditions are at the perfect temperature and humidity levels. This is where the team at the Nature Museum comes in to help.

Scientists at the Museum are working to help caterpillars breed in the laboratory and survive the winters under conditions that mimic their ideal outdoor climate. Using the Baltimore checkerspot as a model for the complex climate needs that both species require, Nature Museum experts continue to work to get closer to helping caterpillars thrive during this time for a healthy release in the springtime.

Regal fritillaries face many challenges during the course of their life cycle. Here are a few of the ways the butterfly poses obstacles for its own survival.

• The regal fritillary caterpillars will only feed on one very specific flower – violets. Not only are these rare flowers its sole source of nourishment, but the violets must also be located in prairies, as the caterpillars will not take to violets in gardens or woodlands.

• The species also lays its eggs late in the season (around the end of August or September) near the violet plants on which the caterpillars will feed.

• Because violets bloom much early in the season by the time they set seed they tend to be hidden beneath other plants, it can be tricky for ecologists and botanists to find them and gather their seeds. As a result, violets continue to be rare on restored prairies. Because eggs are laid as late as September, the tiny caterpillars that hatch live through a cold winter before entering into adulthood in the spring. The Nature Museum continues to work to replicate these conditions in its butterfly lab, as it aims to maintain the populations of several butterfly species.