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The cost of travel: how dispersal ability limits local adaptation in host-parasite interactions


Johnson, Pieter et al. (2021), The cost of travel: how dispersal ability limits local adaptation in host-parasite interactions, Dryad, Dataset,


Classical theory suggests that parasites will exhibit higher fitness in sympatric relative to allopatric host populations (local adaptation). However, evidence for local adaptation in natural host-parasite systems is often equivocal, emphasizing the need for cross-infection experiments conducted over realistic geographic scales and comparisons among species with varied life history traits. Here, we conducted cross-infection experiments to test how two trematode (flatworm) species (Paralechriorchis syntomentera and Ribeiroia ondatrae) with differing dispersal abilities varied in the strength of local adaptation to their amphibian hosts. By pairing 26 host-by-parasite population cross-infections from across the western USA with analyses of host and parasite spatial genetic structure, we found that increasing geographic distance – and corresponding increases in host population genetic distance – reduced infection success for P. syntomentera, which is dispersed by snake definitive hosts. For the avian-dispersed R. ondatrae, in contrast, the geographic distance between the parasite and host populations had no influence on infection success. Differences in local adaptation corresponded to parasite genetic structure; while populations of P. syntomentera exhibited ~10% mtDNA sequence divergence, those of R. ondatrae were nearly identical (<0.5%), even across a 900 km range. Taken together, these results offer empirical evidence that high levels of dispersal can limit opportunities for parasites to adapt to local host populations.

Usage Notes

Directory containing .fastq files for all Pseudacris regilla individuals analyzed in the paper. This directory has been compressed as a tar archive. To uncompress from the command line:$ tar -zxvf pseudacris_regilla_fastqs.tar.gz

This text file contains information on each Pseudacris regilla specimen analyzed with GBS data.  This file contains identification numbers for voucher specimens and their corresponding barcode identification.
This .csv file contains data on experimental infections between hosts (Pseudacris regilla “PSRE") and parasites (R. ondatrae “Rib”, P. syntomentera “Mano”) collected from different source populations.
This .csv file contains data on experimental infections between multiple species of amphibian hosts (P. regilla “PSRE", A. Boreas “BUBO”, T. torosa “TATO”) and the parasite R. ondatrae collected from different source populations.
This .csv file pairwise geographic distance (in km) between locations where P. regilla individuals were sampled and sequenced.
Pairwise FST between populations of P. regilla
pairwise genetic distance (as Nei’s D) between populations of P. regilla 
pairwise genetic distance (as base pair sequence similarity) between parasite samples collected from multiple locations, for both R. ondatrae “Rib” and P. syntomentera “Mano”. 
PCA scores from P. regilla individuals used in experimental crosses, derived from SNP analysis
code for reproducing the statistical analyses (GLMMs) and figures from the paper.


National Science Foundation, Award: 1149308

National Science Foundation, Award: 1754171

National Institutes of Health, Award: RI0 GM109499