Millipedes are thought to be the earth’s first animal to leave water and breathe on land. Now a Georgia College professor is using the under-studied arthropod to see if the world’s changing environment affects this fascinating multi-legged cousin to bugs.
The answer could act as a sign that Georgia forests are losing millipedes and, thus, their No. 1 soldier in ‘waste management.’
Like earthworms – millipedes are responsible for breaking leafy matter into nutritious, healthy soil for trees and plants. They speed up decomposition in forests. Without them, there’s soil erosion and less moisture retention.
“Our natural ecosystems do so much for us. They filter air. They filter water. They provide us with timbers and fuels and sometimes food,” said assistant professor Dr. Bruce Snyder, one of only a handful of scientists in the world studying the ecology of this creeping-burrowing creature.
“The more we change the environment, the more those eco-functions are going to change,” he said. “If the millipedes are affected or an invasive species comes in from Asia or Europe – that can change the entire ecosystem. We can have a whole shift in tree composition.”
Documenting various types of millipedes is an important part of Snyder’s work. Unlike other places in the U.S. and southeast – Georgia’s a “black hole.” There’s little information on diversity of millipedes in its forests.
Snyder and ecology students often rummage through leaves in the forest surrounding Lake Laurel in Milledgeville. They risk chiggers, ticks and poison ivy to find the elusive multi-segmented arthropod, which is found under rocks, mounds of leaves and decaying logs.
Georgia is home to about a hundred different millipedes, compared to 12,000 worldwide. They range from a couple of millimeters long to a gargantuan 12 inches in Africa. The most legs counted on a millipede is 776, and they come in a variety of colors.
Sophomore biology major Christina Cortes recently pulled a 4-inch millipede from it’s tunnel in dead leaves and put it in a container to bring back to the lab. The Fort Lauderdale, Florida, resident was on a pre-med track. But working with Snyder made her want to pursue a career in research. Cortes said she’s learned it’s OK in scientific inquiry to “mess up” and keep trying.
Her research with Snyder focuses on ever-increasing levels of nitrogen in soil and water, which come from over-fertilized agricultural fields or by burning gasoline and other fossil fuels like coal. They hope to pinpoint the level of nitrogen that begins to harm millipedes – decreasing their diversity and ability to decompose leafy matter in woodlands.
Too little nitrogen could mean smaller communities of millipedes. Too much could eliminate entire populations.
Snyder presented research co-authored by Cortes this summer at the International Congress of Myriapodology in Thailand. Cortes laughed, because preliminary data analysis showed millipedes gaining weight and acting “happier” at slightly-elevated levels of nitrogen. They used a small, thin black arthropod from Asia in the 5-week experiment. It gained weight and “tried to escape less,” she said.
“Yeah, they did seem to want to stay in place a little bit more with higher nitrogen levels,” Snyder said. “But that’s a really unscientific way of saying it. We can’t measure contentment.”
This semester, Cortes and other ecology students will test higher levels of nitrogen on multiple types of millipedes. They’ll alter a few research methods too, like giving millipedes a bigger container to live in.
A direct impact on millipede health could signal possible changes in store for Georgia forests. But that’s not necessarily a forecast of doom, Snyder said, because “forests will adapt to change – that’s a general feature to ecosystems.”