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 hybrid zone; parasite’s
hybrid zone is narrower. (c) the host re-establishes panmictic
population while the parasite creates a narrow hybrid zone. (d)as a consequence of the scenario c, the host moves freely across the
whole area but it experiences a “parasite turnover” when crossing the
hybrid zone.
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 it
is not relevant to the discussion of the secondary contact zone (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; depicted on d). SCZ: schematic representation of
the presumed secondary contact zone of the two mtDNA lineages of both
the A. flavicollis and 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 of Polyplax 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 a hybrid zone
(the „parasite turnover 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 designate
the SW and SE sublineages, respectively.
Figure 4. Comparison of maternally inherited markers and
nuclear SNPs. In all parts the two mitochondrial lineages are designated
by different colours: blue=SW, red=SE, and the nuclear hybrids are
identified by purple background. (a) phylogenetic tree based on
complete genomes of L. polyplacis from 23 samples of P.
serrata . (b) phylogenetic tree based on concatenated 11
minichromosomes of P. serrata . (c) PCA analysis of
nuclear SNPs showing the pure parental clusters SW/SE and the hybrid
cluster by the blue, red and purple background, respectively.(d) Admixture analysis of SNP data under K2 parameter
recognizing the parental populations and hybrids.