Polyplax praomydis

Bothma, Johannes C, Matthee, Sonja & Matthee, Conrad A, 2021, Comparative phylogeography between parasitic sucking lice and their host the Namaqua rock mouse, Micaelamys namaquensis (Rodentia: Muridae), Zoological Journal of the Linnean Society 192 (3), pp. 1017-1028 : 1023-1024

POLYPLAX PRAOMYDIS PHYLOGEOGRAPHIC STRUCTURE

The mtDNA TCS network for P. praomydis reveals two haplogroups that could not be connected with 95% confidence ( Fig. 2C ). All P. praomydis individuals from all nine localities sampled in the central and western parts of the country form part of the same haplogroup (central/SW; Fig. 2C ). This pattern is consistent to what has been found in the host and for H. patersoni . The second P. praomydis haplogroup (NE 1) only includes individuals from Mogalakwena (MO; Fig. 2C ) and correspond to the host NE1 clade ( Fig. 2A ). These two haplogroups are separated by a mtDNA sequence divergence of 14.6% (± 2.3%; 40 mutational steps). Although all P.praomydis individuals could be connected with 95% confidence in the nuDNA TCS network, the two haplogroups (retrieved in the mtDNA data) differ by two mutational steps ( Fig. 3C ). The TrNef+G model (nst = 6; rates = gamma) of sequence evolution was assigned for the first and third codons, whilst the K81 model (nst = 6; rates = equal) was assigned to the second codon. The concatenated mtDNA and nuDNA analysis reveals significant posterior probability and high bootstrap support for both the monophyly of the NE 1 lineage and the central/SW lineage (Supporting Information, Appendix S1). Analyses of molecular variance support significant differentiation among the haplogroups of P. praomydis with 93.6% (P <0.05) of the mtDNA variation assigned to this category and a further 5.5% (P <0.05) assigned to variation among localities within haplogroups ( Table 2). A similar picture is obtained for the nuclear DNA analyses where 92.9% (P <0.05) of the variation is confined to variation between haplogroups ( Table 2). Polyplax praomydis populations show a near absence of gene flow among sampling sites [mtDNA Фst of 0.99 (P <0.05); nuclear Фst of 0.97 (P <0.05); Table 2]. Significant mtDNA pairwise Фst values also support the differentiation among almost all sampling localities (Supporting Information, Appendix S2). Nonsignificant pairwise Фst values are confined to pairwise comparisons between Tswalu (TS), Postmasburg (PB) and Rooipoort (RP) sampling localities (Supporting Information, Appendix S2).

Co-divergence

CO- PHYLOGENY

All parasite and host individuals belonging to the CSW clade form a strongly supported monophyletic group (96% bootstrap support; 1.00 posterior probability; Supporting Information, Appendix S1). Conflicts between the parasite and host trees are all confined to the four localities found in the NE1 and NE2 clades (Supporting Information, Appendix S1). The JANE co-phylogenetic reconstruction between M. namaquensis and H. patersoni reveals that the most parsimonious solution with a total cost of three, includes three co-divergences, one host switch and one loss ( Fig. 4 ). Both of the statistical analyses indicated non-significant co-phylogeny between the M. namaquensis and H. patersoni , with P = 0.39 and P = 0.27 for random tip mapping and random parasite tree, respectively.

Figures

Figure 2. MtDNA haplotype networks for: A, M. namaquensis; B, H. patersoni; C, P. praomydis. Haplogroups that could not be connected with 95% confidence are identified by shapes/circles. The average percentage COI sequence divergence between the different haplotypes and the number of mutational steps between haplogroups are indicated. The geography of haplogroups are indicated in (D), where black, red and blue circles indicate the haplogroups of M. namaquensis, H.patersoni and P.praomydis separately. Colours of sampling localities correspond to the colours used in the haplotype networks (A–C).

Figure 3. NuDNA haplotype networks for: A, M. namaquensis; B, H. patersoni; C, P. praomydis. Haplotype colours correspond to the colours of the different localities from where the samples were collected in (D).

Figure 4. Phylogenetic reconciliation of H. patersoni and M. namaquensis retrieved from JANE after the five types of evolutionary events (legend) was tested for. The locality abbreviations refer to the localities in Figure 1 and CSW refers to the central/south-western haplogroup.