Figure legends
Figure 1. Different scenarios of the secondary contact outcomes in a host-parasite association. (a) the host re-establishes a panmictic population while the parasite differentiates into two separated species, which keep spreading and eventually live in sympatry.(b) both host and the parasite create HZ; parasite’s HZ is narrower. (c) the host re-establishes panmictic population while the parasite creates a narrow HZ. (d) as a consequence of the scenario c, the host moves freely across the whole area, while parasite’s lineages are “filtered” by the HZ.
Figure 2 . Genetic background of Apodemus spp. andPolyplax serrata adopted from Martinů et al., 2018. (a)The main genetic pattern of Apodemus hosts relevant to this study. Inner mtDNA structure of A.sylvaticus is ignored since not relevant to the discussion of the SCZ (see the text). (b)Geographic distribution of the hosts: both spp. co-occur across Europe with their intraspecific mtDNA clades randomly dispersed. Both spp. are parasitized by the non-specific lineage (N) of the lice shown on the d.(c) Two mtDNA lineages of A. flavicollis which in addition to the N lineage are parasitized by the specific lineage (S; deepicted on d). SCZ: schematic representation of the presumed secondary contact zone of the two mtDNA lineages of both the A. flavicollisand the S lineage of the parasite. While the host‘s lineages dispersed across the whole Europe after glaciation, the parasite‘s lineages remain confined to the two exclusive areas (red and blue) with a narrow hybrid zone (the violet line). (d) The main genetic pattern ofPolyplax serrata showing ecological complexity of this parasite: the N and S lineages live in sympatry but differ in the degree of host specificity (single host vs two hosts); the SW (specific west) and SE (specific east) lineages create hybrid zone (the „cleansing zone“) which transverses panmictic population of the host.
Figure 3. (a) Distribution of the P. serrata S lineage samples analyzed in Martinů et al., (2018). (b) Detailed distribution of the samples used in this study. Blue and red designates the SW and SE sublineages, respectively.
Figure 4. Comparison of maternally inherited markers and nuclear SNPs. In all parts the two lineages are designated by different colours: blue=SW, red=SE. (a) phylogenetic tree based on complete genomes of L. polyplacis from 12 samples of P. serrata . (b) phylogenetic tree based on concatenated 11 minichromosomes of P. serrata . (c) PCA analysis of nuclear SNPs. The light blue triangle designates a complete set of the SW samples, including the 98d_Pro_SW which clusters together with the SE samples (the overlapping red shape); the deep blue triangle designates SW lineage in exclusion of the 98d_Pro_SW sample.(d) ML tree based on the SNPs showing the 98d_Pro_SW sample clustering within the SE clade.