Eurymerodesmus varius is a species of flat-back millipede with a range that expands across the Southeastern United States. While commonly encountered, Eurymerodesmus are relatively small and thus are overlooked and understudied. In fall of 2023, millipedes were found crawling into buildings on Georgia Southern University’s Armstrong Campus in Savannah and dying en masse. Because parasites are known to elicit behavioral responses in some infected hosts, we dissected the dying millipedes and surveyed them for nematodes and other potential parasites. We found a high (>65%) prevalence of gregarine Apicomplexans within the intestines and body cavity of male and female millipedes. While gregarines are often considered to be parasites that can cause behavioral modifications in their hosts, they can also form commensalistic or mutualistic partnerships. We determined the presence, abundance, and types of gregarines found in both dying and healthy E. varius specimens
