treeducken: An R package for simulating cophylogenetic systems

1. Cophylogenetic methods describe discordance between non-independent phylogenies. 2. Simulation is necessary for testing cophylogenetic methods, but few simulators exist that are capable of generating data under explicit and biologically meaningful models. 3. We present an R package, treeducken, for simulating host-symbiont evolution and gene-tree-species-tree evolution. 4. treeducken provides a straightforward and reproducible interface for simulating cophylogenetic data. This allows easier performance testing of methods and has potential applications in machine learning (ML) and approximate Bayesian computation (ABC) approaches.