Shining a Spotlight on an Ancient Partnership Between Fungi and Millipedes

Angie Macias, PhD Student¹
Shelby Meador, Undergraduate Researcher²
Brian Lovett, Post-doctoral Researcher¹
Matt Kasson, Associate Professor of Plant Pathology & Mycology¹

¹Division of Plant and Soil Sciences, West Virginia University

²Department of Biology, West Virginia University

Colony of Brachycybe lecontii observed in August 2019. Photo by Matt Kasson.

The Kasson Lab’s quest to document the biodiversity associated with fungivorous millipedes continues, thanks to a 2021 National Geographic Society Grant. This award funds a series of expeditions to collect fungus-loving millipedes across the U.S. from West Virginia to Florida to California and back. Millipedes represent some of the earliest known terrestrial animals, dating back to the early Devonian period. Around 250 million years ago, a group of millipedes began to feed exclusively on fungi, a rare diet among animals. The fungal communities of 98% of known fungus-feeding millipede species in the U.S. have never been studied. For our work, we will sample nearly half of all known diversity of these fungus-feeding millipedes. Specimens we collect are destined for culturing and high throughput amplicon sequencing to characterize their associated fungal communities. Considering the long evolutionary history of both fungi and millipedes, these studies may reveal some of the earliest fungal associations with terrestrial animals. Based on our previous work on Brachycybe lecontii, we expect that studying these millipedes will uncover numerous fungi currently unknown to science. By examining fungal associations in this largely overlooked group of animals, we aim to explore the role fungi play in the successful and ancient partnership between fungi and millipedes.

Map of U.S. showing states (orange) and counties (red) to be sampled for this project.

Our first expedition scheduled for March 2021 will target 5 millipede genera across 13 state and county parks, botanical gardens, and National Forest lands in South Carolina, Georgia, Alabama, and Florida. All required collection permits have either been secured already or are being finalized, an important first step for any fungal biodiversity study. While most of our target millipedes are native to the eastern U.S., one millipede, Rhinotus purpureus is introduced and rapidly expanding its range across southern Florida, possibly with a community of exotic fungi it has brought along for the ride. Embarking upon this trip in the era of COVID has presented many challenges we could not have anticipated when we proposed this work early in January 2020, but we plan to use every precaution to ensure a safe and successful trip. Other trips will follow this summer, including expeditions to the central Appalachian Mountains, the southern tier of New York and to Ohio, and eventually (Fall 2021) to Arizona and California, where we hope to collect a majority of our 25 target species.

Ph.D. student Angie Macias examining a Brachycybe lecontii collected at Bad Branch State Nature Preserve in Letcher County, Kentucky in August 2019.

If you are interested in following our progress, check out our project Twitter account @MillipedeEats. We are also using the Twitter hashtag #MillipedeMondays to showcase the various fungivorous millipedes we hope to collect during this work. We will be submitting observations to iNaturalist to help better populate the map for these charismatic, underappreciated arthropods.

We look forward to sharing our results over the next year!