Chasing the rare arogos skipper butterfly from Florida fields to lab

GAINESVILLE, Fla. --- With their triangular shape and golden-orange wings, the eastern arogos skipper (Atrytone arogos arogos) butterflies seemed to wave down the passing crew of researchers at Herky Huffman/Bull Creek Wildlife Management Area near Orlando, Florida.

“You can just drive along and see them perched on the flowers. You don’t even have to get out of the car,” said Jaret Daniels, a curator at the Florida Museum of Natural History’s McGuire Center for Lepidoptera and Biodiversity. When the crew does approach, “you can just pick the individuals off the flower with your hands. It’s totally bizarre. It breaks all the rules of what you think normal butterflies do,” he said.

The insects may be easy to spot, but only if you know where to look. Today, encounters with the rare arogos skipper are uncommon.

Once found across much of the East and Gulf coasts of the U.S., the species spanned from New Jersey to Louisiana. Today it has been reduced to a small number of primarily isolated populations living in a variety of open, grassy landscapes. Many of these habitats have been lost to expanding agriculture and urban development or degraded due to fire suppression.

Central Florida remains a stronghold, with the population at Bull Creek just one of a handful known to exist in the state. The species may be a contender for federal protection, but wildlife managers need more data to build a compelling case. This is why the Florida Fish and Wildlife Conservation Commission reached out to the museum’s Daniels Lab and the Florida Natural Areas Inventory to collaborate on a two-year project in which they will survey portions of the state to learn where these butterflies live and observe what conditions the species needs to thrive.

Often the trick to finding small butterflies is to locate the host plants where they lay their eggs and their caterpillars develop, or find the nectar sources upon which the adults feed. For the eastern arogos skipper, Bull Creek offers both.

A dirt road cuts through the park and crosses fields of lopsided Indiangrass (Sorghastrum secundum), a known host plant for this species and several other skippers. For most of the year, the grass is indistinct, but by late summer it sends up tall bronze and yellow flower spikes that drape to one side of the stalk. Eastern arogos skippers lay individual eggs on the undersides of the grass blades, providing the emerging caterpillars an easy source of food. Meanwhile, the adult butterflies get their nourishment from various wildflowers. As the fall season brings fewer nectar options, one — the rayless sunflower (Helianthus radula) — becomes all the more important.

“Out here, the lopsided Indiangrass almost appears to go on for miles in every direction. The host isn’t limited. What’s apparently limited is their source of nectar,” Daniels said. “The rayless sunflower is a super attractor. It brings everything in.”

“Super attractor” may not be the first phrase that comes to mind when observing the rayless sunflower. From a distance, the tall flowers could easily be mistaken for last season’s shriveled seed heads stubbornly persisting among the landscape’s long grasses.

But up close, what appears lifeless transforms into a bloom of dark maroon florets clustered on the tip of a bright green stem. Bristly hairs cover the otherwise bare stem, which sticks up from a hairy carpet of thick, round leaves covering the ground beneath the flower patch. Even lacking vibrant colors and showy petals, this species clearly has its own allure. At Bull Creek, tiny tree frogs, grasshoppers and various spiders are just as likely as butterflies to be perched on the swaying flower tops.

Clutching their butterfly-filled nets, the researchers regrouped beneath the open hatch of their SUV – a makeshift lab workstation in the field. With a trained eye, Daniels separated the females to take back to the lab in Gainesville. After taking a genetic sample and marking their wings with a Sharpie, they released the males. Back at the lab, scientists will analyze the DNA to evaluate any differences that exist among populations.

“We don’t know how connected these populations are,” Daniels said. “Are they moving across the broader landscape between nearby wildlife management areas? Or, because of different management plans or other barriers, is there movement at all?”

Spanning 23,000 acres, Bull Creek contains one of the largest remaining grasslands in the state. Its size and unique management plan may help explain why the eastern arogos skipper persists there.

“This butterfly has declined in many areas because of habitat loss and other forces,” Daniels said. “But I suspect one of the main driving factors affecting this butterfly is land management  and how it aligns with the species’ needs. You might manage habitat for other species or uses, but maybe that isn’t quite what this skipper wants. It has a sweet spot for what it likes.”

One important consideration is the prescribed burn schedule. Fire is an important habitat management tool, but its frequency, intensity and scale can make or break conditions for certain wildlife and vegetation. At Bull Creek, the land managers burn on a three-year cycle and divide the large landscape into smaller burn units, allowing the butterfly to move to safe spaces when a fire moves through an area.

“Here you have thousands of acres, so you have refugia built into the system. That is undoubtedly one of the reasons this butterfly is thriving out here and what makes this a pretty unique area,” Daniels said. “But it is perilous. If a new manager comes in and decides to do something different, if a catastrophic wildfire happens, if there’s a drought … that could all knock it back. It’s tenuous at best.”

Back at the lab, researchers are studying the life cycle of the eastern arogos skipper, which they hope will help inform land managers across the state on how best to support this butterfly.  Some 15 female butterflies were brought from Bull Creek and surrounding wildlife management areas to the Daniels Lab, where each was set up with lopsided Indiangrass and cotton swabs soaked in Gatorade, a substitute for nectar.

“The broader goal is to do as much as we can to learn more about them in all life stages. Breeding and raising these organisms in captivity is often pioneering because nobody has really done it before,” Daniels said. “Every species is different, so trying to figure out what works and what doesn’t takes a lot of tinkering.”

Beyond maintaining a large and healthy population in the lab, the researchers will also experiment with different host plants. While the lopsided Indiangrass is a well-known host, the eastern arogos skipper has been observed to use several other grass species across its range, and scientists are eager to learn more about their preferences.

“Will the butterflies lay eggs on all of these grasses? Will they lay more eggs on certain grasses?” said Kristin Rossetti, the conservation coordinator of the Daniels Lab. “And after these observations, we’ll assess what the larvae can tolerate eating.”

Rossetti and the crew observed and recorded notes on the eastern arogos skippers throughout the fall and winter. By the end of October, more than 200 eggs had hatched into translucent green larvae. Most of the caterpillars remained on the lopsided Indiangrass, but others were placed on the alternate grass species.

About the size of a grain of rice, the young caterpillars are nearly indistinguishable from the grass surrounding them. Each day, the scientists carefully peer through the blades to find the caterpillars and record their development. Larger caterpillars tend to be healthier ones, so scientists can use these measurements to determine whether the caterpillars prefer one type of grass over another.

As they eat the grass, the caterpillars construct individual shelters by using silk to stitch the edges of a blade together into a protective tent. As they grow, the caterpillars construct larger shelters by connecting several blades. In colder climates, the larvae go into diapause, a process akin to hibernation in mammals, until spring, but in north Florida, some larvae may remain active all winter long.

As the weather warms this spring, the arogos skippers will pupate and emerge as butterflies. The research team will continue to observe and rear them throughout their entire life cycle. For now, the Daniels lab is focused on collecting as much data as possible to develop a better understanding of the species and support its future in the Sunshine State.

“Wildlife managers may eventually think about more ambitious conservation approaches like captive reintroduction for this skipper,” Daniels said. “The more we learn, the more we’re poised to inform how to successfully safeguard and help recover these declining populations.”