Graduate student Anne Sawl cares for dozens of rare Florida scrub millipedes in a USF St. Petersburg lab, where the arthropods recently reproduced and their offspring are now being raised. Credit: University of South Florida

Before scientists even knew how many Florida scrub millipedes were left in the wild, a quiet breakthrough happened in a University of South Florida lab. The rare, giant millipedes reproduced in captivity.

The unexpected arrival of baby millipedes is the result of meticulous conservation research led by graduate student Anne Sawl, whose work is uncovering long-missing information about a species found nowhere else in the world.

Sawl studies the rare Florida scrub millipede (Floridobolus penneri), which resides along the Lake Wales Ridge. Like other arthropods, the Florida scrub millipede has an exoskeleton, a segmented body and more than 100 legs. One of the largest in North America, it can grow up to 4 inches long and spends most of its life underground, emerging at night to move through Florida’s dry, sandy terrain.

The millipede plays an important role in the state’s scrub ecosystem.

"They are crucial to nutrient recycling," Sawl said. "By feeding on dead leaves and plant material, they digest it and excrete nutrients that fertilize the soil and support plant growth in these otherwise nutrient-poor sands."

As part of USF’s conservation biology master’s program, Sawl’s research has taken her on overnight trips to the Lake Wales Ridge, where she carefully excavates living specimens. Several of the millipedes are now housed in a lab on the St. Petersburg campus.

Recently in the lab, she came across an unexpected discovery: baby millipedes hatched in captivity.

"One day, I was moving dirt near the roots of the plant and noticed a tiny white speck," Sawl said. "It caught my eye. I picked it up and realized it was a baby millipede. After so much trial and error in the lab, I was completely flabbergasted that they had reproduced."

Getting the millipedes to reproduce was not easy. Sawl experimented with different groupings, but nothing worked. Success finally came when she moved the millipedes into a kiddie pool filled with native plants collected from the ridge.

That breakthrough marked a welcome surprise for a species that scientists know little about. The Florida scrub millipede is endemic and considered imperiled due to extensive habitat loss. Sawl discovered they had not been comprehensively surveyed in nearly two decades. By documenting where the millipedes still exist and how many remain, Sawl’s research is filling a critical knowledge gap and could lay the groundwork for future conservation efforts.

Sawl’s work examines the abundance and distribution of the Florida scrub millipede. She compares it with a more widespread species, the smoky oak millipede (Narceus gordanus), which ranges as far north as the Carolinas. The two species live side by side in central Florida’s dry, infertile, quartz-rich sands.

Millions of years ago, fluctuating sea levels transformed Florida’s ridges into isolated, island-like systems. Species stranded on these ridges evolved independently, resulting in today’s high concentration of rare and endemic life in this region.

The Lake Wales Ridge, the oldest and highest of these systems, is now among the most heavily altered by development. Since pre-settlement times, Sawl said an estimated 85% of the ridge’s natural habitat has been lost to agriculture, housing and roads.

Sawl’s fieldwork spans both preserved and developed sites along the ridge. Preliminary findings indicate that the more widespread smoky oak millipede occurs in higher numbers at each site. In contrast, the Florida scrub millipede remains more restricted, persisting in mostly developed areas. Sawl also found that both species share a mite previously thought to be host-specific, and that the millipedes favor fungi and mushrooms over some plant material scientists once expected.

Sawl’s advisor and mentor, Deby Cassill, praised her work.

"Anne has taken a group of animals most people overlook and produced multiple chapters of publishable research with brand new information," Cassill said. "Millipedes might not be glamorous, but they are ecological champions in these fragile habitats."

The appearance of baby millipedes in the lab has opened an exciting avenue for future research. Cassill is already applying for grants to support Sawl after she receives her master’s degree this spring, allowing her to continue her work at USF at the doctoral level.

Citation: Rare Florida scrub millipedes reproduce in captivity for the first time (2026, January 21) retrieved 21 January 2026 from https://phys.org/news/2026-01-rare-florida-millipedes-captivity.html

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