During the months of June, July and early August, the Kankakee Sands prairies are aflutter with the stunning regal fritillary butterfly (Speyeria idalia). Though commonly seen at Kankakee Sands, regals are very rare elsewhere in Indiana.
Often referred to as “Flowers of the Sky”, these large, showy butterflies are easy to spot on the prairie. They are roughly the same size as monarch butterflies, four inches from wingtip to wingtip, and they’re strong fliers like monarchs, too. In fact, I’ve watched regals chase monarchs across the prairie, and watched monarchs chase regals. I’ve always wondered what would happen if they caught one another…
From afar, a regal fritillary butterfly could easily be mistaken for a monarch. Both are large and orange. The forewings of the regal are orange, with black spots, but the smaller hind wings are dark in color. It’s these dark hindwings that set them apart from monarchs when you catch a quick glimpse of them in the field. Females have white spots on the hind wing, and males have both white and orange spots on the hind wing.
In late June, the males are the first to emerge from their chrysalis (a chrysalis is to a butterfly what a cocoon is to a moth). June 12 was the exciting day that I saw a regal male at Kankakee Sands for the first time this year. Female regals emerge two to three weeks later than the males. Mating begins soon after females take to the wing.
In August, females lay their eggs, singly, on the underside of dead vegetation near violet plants. Female regal butterflies are capable of laying 1,000 eggs in their short, two month lifetime. Eggs hatch in the fall, and the tiny two-millimeter long (roughly the width of a sesame seed) caterpillars go into diapause, or a state of suspended development, for the winter. In the spring of the following year, caterpillars are very hungry and feed exclusively on violets. The larvae grow from sesame seed size to almost two inches by eating violet leaves. Then they create a chrysalis and over the course of two to four weeks, transform into a butterfly.
Violet plants are the sole source of food for regal caterpillars. At Kankakee Sands we have been planting the seeds and plants of lance-leaved violet, arrow-leaved violet, bird’s foot violet, and common violet to increase the food source for the regals. Adult regals nectar on many different types of flowering plants, including milkweeds, goldenrods, and mints.
Unlike the monarch, the regal fritillary does not migrate. After the adult butterfly emerges from its chrysalis, the regal remains close to the area from which it emerged. However, in the late summer, when it is time to lay eggs, the regals move larger distances, covering one to four miles.
Regals were once common throughout the United States, from Eastern Colorado to Maine. Today, mostly due to habitat loss, it is found only in two states east of Indiana, in Pennsylvania and Virginia.
In Indiana, just twenty years ago, the state-endangered regal occurred only at Beaver Lake Nature Preserve. But now, thanks to the conservation work at Kankakee Sands, Willow Slough Fish and Wildlife Area, Conrad Station Savanna and other northwest Indiana locations, regals can be seen throughout the sand prairies and sand savannas of northwest Indiana. The regal fritillary is a true testament to the power of connecting natural areas and conserving large open spaces.
July is a great month to see the regal fritillaries, and Kankakee Sands is the place. I recommend a leisurely hike on Grace Teninga Discovery Trail (located off CR 600 N, east of US 41), and a trip to the Kankakee Sands Nursery (located on CR 250 N, east of US 41, across from North Newton High School) for the best views. Enjoy the flowers of the prairie, and the flowers of the sky!