Lineage-specific trait variation generates widespread, contemporaneous coexistence and competitive exclusion dynamics in an invasive, multihost wildlife parasite

Invasive and highly virulent parasites are being transported to new locations and into novel hosts by anthropogenic activities. Repeated introductions lead to interactions amongst genetic lineages, resulting in competitive exclusion, coexistence, or cycling through a combination of the two. Here, we describe interactions between the same two lineages that demonstrate both ends of the exclusion/coexistence continuum. We report intra-lineage trait variation of the multihost amphibian parasite Batrachochytrium dendrobatidis driving contrasting outcomes of inter-lineage interactions on two continents. Trait variation in the global pandemic lineage, BdGPL, is responsible: In Europe, BdGPL competitively constrained the distribution of the other, BdCAPE, while in Africa, BdGPL and BdCAPE can mutually invade host populations when the other is already resident, leading to coinfections and recombination. That these contrasting outcomes are prolonged and contemporaneous illustrates how epidemiological models of invasive wildlife parasites need to account for trait variation both within and across lineages.