The coevolutionary relationship between fungus-growing ants (Formicidae: Attini: Attina) and their symbionts has been well-studied in the Panamanian rainforests. To further understand the ecological context of these evolutionary relationships, we have examined the population genetic structure of the fungus-growing ant species Mycetomoellerius mikromelanos Cardenas, Schultz, & Adams 2021, in the Panama Canal Zone. We specifically investigated the presence of population structure, the significance of geographic features (i.e., creeks) limiting gene flow, and relatedness between ant colonies. To accomplish this, we genotyped 85 ant colonies from nine creeks across an approximately 30 km transect in Parque National Soberanía, Panama using double digest restriction-site associated DNA sequencing. We did not find distinct population structures using two genetic clustering methods; however, we did detect an effect of isolation by distance. Furthermore, related colonies were frequently detected on the same creek or neighboring creeks, and some at further geographic distances. Collectively, these findings demonstrate that new colonies tend to establish on natal creeks and occasionally on distant creeks following long-distance dispersal events. We discuss how population genetic patterns reveal the natural history of M. mikromelanos in Parque National Soberanía and how these results fit into the context of fungus-growing ant mutualisms.

DNA was extracted from a single worker from colonies of Mycetomoellerius mikromelanos found in Parque National Soberanía, Panama. Following the ddRADseq protocol of Peterson et al. (2012) digestion was performed with restriction site enzymes Msp1 and Spfl-HF (New England Biolabs, Inc., Ipswich, Massachusetts, USA). Genomic fragments of 250-600 bp in length were selected and sequenced 150 bp paired-end reads at Nationwide Childrens Hospital in Columbus, Ohio USA on an Illumina HiSeq 4000. SNP data were QC'd and trimmed (FastQC v0.11.7; Andrews 2018; trimmomatic v0.38; Bolger et al. 2014), and SNP discovery was performed with ipyrad (v0.9.31; Eaton & Overcast, 2020).

• Andrews, S. (2018). FastQC (v0.11.7). Barbraham Institute. https://github.com/s-andrews/FastQC/releases
• Bolger, A. M., Lohse, M., & Usadel, B. (2014). Trimmomatic: A flexible trimmer for Illumina sequence data. Bioinformatics, 30(15), 2114–2120. https://doi.org/10.1093/bioinformatics/btu170
• Eaton, D. A. R., & Overcast, I. (2020). ipyrad: Interactive assembly and analysis of RADseq datasets. Bioinformatics 36(8), 2592–2594. https://doi.org/10.1093/bioinformatics/btz966
• Peterson, B. K., Weber, J. N., Kay, E. H., Fisher, H. S., & Hoekstra, H. E. (2012). Double digest RADseq: An inexpensive method for de novo SNP discovery and genotyping in model and non-model species. PLoS ONE, 7(5), 1–11. https://doi.org/10.1371/journal.pone.0037135

*unix based CLI, python, R