From pavement to population genetics: Using citizen science data and ddRADseq to characterize the long-established pavement ant, Tetramorium caespitum, in North America

The pavement ant, Tetramorium caespitum, has been established in human-modified environments in the United States since the mid-19th century, but little is known of its introduction history and subsequent population dynamics. Recent discovery of multiple cryptic species in the native range of T. caespitum suggested the possibility that pavement ants in North America were comprised of multiple species in the complex. This study used ants collected through the School of Ants citizen science project to 1) determine that ant DNA from citizen science collections is appropriately preserved for molecular genetic research and 2) confirm that introduced pavement ants in North America comprise a single European species, T. sp. E (aside from the Asian T. tsushimae). Further, we find that the range of the pavement ant in North America is significantly larger than previously recorded – present in at least 7 additional U.S. states. Population genetic analysis of T. sp. E using double-digest Restriction-site Associated DNA sequencing (ddRADseq) suggests that this species may be an appropriate model organism demonstrating how metropolitan species have spread and established as a result of the urbanization of North America.