MOUNT VERNON, Mo. – Seventeen adult king fritillary butterflies spread their orange wings and took flight earlier this month over Linden’s Prairie as part of a project between the Missouri Department of Conservation and Missouri State University to maintain and restore vulnerable species.
Regal fritillary, with the scientific name Speyeria idalia, is a species of state conservation concern that is in decline and vulnerable to local extinction due to habitat loss, restricted range, widespread declines and other factors, according to the department.
Steve Buback, the department’s natural history biologist, said the species was originally applied for listing under the Endangered Species Act in 1989 and again in 2013. Since then, the department of the Missouri Conservancy collects data on where royal fritillaries are still located throughout the state.
“Of the 106 former locations of the species, we found about 70, which was pretty good,” Buback said. “At each of these sites, we developed population estimates to determine not only where the species was still present, but how it was doing. We walked a set distance and counted the number of fritillaries we saw along each transect and used this to develop population estimates. After that, we looked at the life history of the species and some of the weak spots that might be in its life cycle.
Linden’s Prairie near Mount Vernon, protected by the Missouri Prairie Foundation, is the new home of the royal fritillaries. It has more than 190 species of native plants, including violets, the favorite food of caterpillars. Adults are attracted to native flowers, such as butterfly weed, common milkweed, and pale purple coneflower. Female royal fritillaries also need nectar for the whole summer.
“Missouri Prairie Foundation’s Linden’s Prairie is a fantastically diverse and beautiful, original, untilled prairie. On its 171 acres there are abundant prairie violets, which will serve as host plants for the royal fritillary caterpillars”, said Carol Davit, director of the foundation. director. “Large populations of many prairie species like the royal that were once more common in Missouri are now rare due to the loss of prairie habitat in our state over the past 200 years. Linden’s Prairie and the other 29 properties of the foundation across the state provide habitat for many species of conservation concern like the royal, protected for the benefit of current and future Missourians.”
Chris Barnhart, professor emeritus of biology at Missouri State University at Springfield, and his wife, Debra, participated in the project and released the 17 royal fritillary butterflies this month.
“What we’re trying to do with this project is find methods, so that we can make some, put them in a meadow and have them restart, if they go out,” he said. declared. “It also helps us understand what their overwintering needs are.
Buback said he was able to release about 3,000 caterpillars into the Missouri grasslands throughout the two-year project to help revive the population. The team had identified grasslands that originally had king fritillaries but no longer had them and where populations remained too low to detect, and started there. Release sites include La Petite Gemme Prairie in Polk County and the Diamond Grove Prairie Conservation Area in Newton County.
“We’ll be returning in mid-June to each of these sites to assess if we see adults flying, that’s how we’ll measure success,” Buback said.
While monarch butterflies stick to fields and grasslands, royal fritillaries are restricted to tall grass prairies. Royal fritillaries feature orange and black colors and are sometimes confused with monarch butterflies, their distant cousins.
“They’re called the large fritillaries, and it’s a really interesting group of butterflies,” Barnhart said. “They are located in the northern hemisphere. In the United States I believe we have 16 species of Speyeria, and in Missouri we have three. We raise the Great Spangled Fritillary for the Butterfly House in Springfield every year. These are easy.
“The other two Missouri fritillary species are both considered threatened,” he added. “In fact, one of them isn’t even in Missouri anymore. Then there’s the royal, which isn’t a rare butterfly as long as you’re in the right habitat. In this case, it is the habitat that is in danger.
Once covering almost a third of America, grasslands have become scarce and are one of the most threatened ecosystems in the world. Barnhart said Missouri is one of the best places to see the prairie, but it’s scattered in small pieces.
“The royals stay here year-round, and if you lose them in a patch of grassland, they may not come back for decades, if at all,” Barnhart said.
Since 2014, the Missouri Prairie Foundation has protected more acres of untilled original prairie than any other agency or conservation group in Missouri during that time, Davit previously told The Globe. The foundation has protected over 5,000 acres of prairie and owns over 4,300 acres of prairie in 30 parcels across the state.
Cycle of life
The royal fritillaries only have the opportunity to reproduce once a year, which may also be contributing to its rapid decline, according to the Missouri Department of Conservation. It takes about a month for a royal fritillary butterfly to mature, but other species like the monarch butterfly can grow from egg to pupa in just two weeks, Barnhart said.
“Most butterflies overwinter as eggs or pupae, which are fairly stable ways of overwintering, but fritillaries overwinter as caterpillars, and we think there is significant mortality during the winter” , Buback said. “We worked with Dr. Barnhart to find ways to quantify that, what they needed during the winter, and if we could manipulate our habitats to better provide that necessary environment.”
Last August, during the mating season, groups collected adult king fritillary butterflies from five grasslands to promote genetic diversity. They were raised in Temple Hall on the campus of Missouri State University, where they laid their eggs. After hatching in September, the caterpillars hibernated in incubators through the winter.
The caterpillars were placed in incubators operating at a temperature just above freezing. Barnhart said overwintering the caterpillars was a tricky process, but it was successful.
“We kept them for about a month and kept them individually in little houses made out of white paper bags,” he said. “We fed them every day, collected their eggs and counted them. Then the eggs hatch in the fall and the small caterpillars do not feed. We put most of them away for the winter and kept them temperature and humidity controlled, which is a little tricky. That’s one of the things we’ve been working on is how to overwinter the caterpillars. They can do it on their own in the meadow, but when you bring them inside it’s different.
Buback said Barnhart’s research into the species’ reproductive cycle had been beneficial.
“We’ve learned a lot about the species with the work he’s done, and one of the things we’ve found is that winter humidity seems to be more important than temperature,” he said. “The caterpillars can survive fairly cold temperatures but can easily become dehydrated during the winter, leading us to speculate that winter snow cover may be a significant contributing factor in maintaining this species in a landscape. Unfortunately, it is something that is entirely beyond our control.
Males begin to emerge from pupation in early summer and females arrive a few days later. Then the reproductive cycle begins again for the females, who don’t lay their eggs until late summer or early fall, according to the Missouri Department of Conservation.
“We don’t really know how likely the project is to succeed, but we’ll know here in a few weeks when we go out and start surveying the adult populations at the release sites,” Buback said. “We want to see if this is a practical and feasible way to maintain this species, if our normal grassland management is not doing what is necessary for the species.”
The ministry plans to continue surveying royal fritillary release sites over the next few years to monitor their populations and see if the reintroduction process is beneficial to the species.
“If the butterflies manage to survive this year, it’s pretty important for us to see if they stick around for three or five years,” Buback said.