Figure 1.
(1) The phylogenetic information encapsulated by the host-parasite (H-P) tanglegram gives way to two distance matrices of host and parasites, and a binary matrix of host-parasite (H-P) links. (2) The distance matrices are transformed by Principal Coordinates. (3) The H-P link matrix (A) is converted into an identity matrix to account for multiple host-parasite associations. (4) Rows in the Principal Component matrices are duplicated (arched arrows) following the order dictated by the identity matrix. (5) The extended Principal Coordinate matrices (X and Y) are centred by mean column vectors and subjected to Procrustes analysis, where the parasite configuration is rotated and scaled to fit the host configuration. The fit can be visualised in a Procrustes superimposition plot. (6) The analysis yields a global goodness-of-fit statistic (), whose significance can be established by a randomization procedure, and individual link residuals that can be further analysed to establish the contribution of each H-P link to the global fit.
Figure 2.
Phylogenetic trees of pocket gophers (left) and chewing lice (right).
Blue lines represent host-parasite associations observed in nature. Gopher species abbreviations: Ccas: Cratogeomys castanops; Cmer: C. merriami; GburA: Geomys bursarius halli; GburB: G. bursarius majusculus; Gbre: G. breviceps; Gpers: G. personatus; Ocav: Orthogeomys cavator; Oche: O. cherriei; Ohet: O. heterodus; Ohis: O. hispidus; Ound: O. underwoodii; Pbul: Pappogeomys bulleri; Ztri: Zygogeomys trichopus; Tbot: Thomomys bottae; Ttal: T. talpoides. Louse species abbreviations: Gact: Geomydoecus actuosi; Gcha: G. chapini; Gche: G. cherriei; Gcos: G. costaricensis; Gewi; G. ewingi; Gexp: G. expansus; Ggeo: G. geomydis; Gnad: G. nadleri; Gokl: G. oklahomensis; Gpan: G. panamensis; Gpero: G. perotensis; Gset: G. setzeri; Gtex: G. texanus; Gtho: G. thomomyus; Gtri: G. trichopi; Tbar: Thomomydoecus barbarae; Tmin: T.minor.
Figure 3.
Tanglegram depicting the associations between 20 fishes and 51 Dactylogyrus spp (Monogenea).
Lineages 1–3 of Dactylogyrus correspond to those recognized by Šimková et al. [32]. Fish species abbreviations: Aalb: Alburnus alburnus; Aasp: Aspius aspius; Abra: Abramis brama; Bbal: Ballerus ballerus; Bbar: Barbus barbus; Bbjo: Blicca bjoerkna; Bsap: Ballerus sapa; Caur: Carassius auratus; Ccar: Cyprinus carpio; Cide: Ctenopharyngodon idella; Cnas: Chondrostoma nasus; Gcer: Gymnocephalus cernua; Ggob: Gobio gobio; Lidu: Leuciscus idus; Ppar: Pseudorasbora parva; Ppho: Phoxinus phoxinus; Ralb: Romanogobio albipinnatus; Rrut: Rutilus rutilus; Scep: Squalius cephalus; Sery: Scardinius erythrophthalmus. Dactylogyrus – specific-name abbreviations: achm: achmerovi; alat: alatus; amph: amphibothrium; anch: anchoratus; auri: auriculatus; bore: borealis; caba: caballeroi; carp: carpathicus; chon: chondrostomi; chra: chranilowi; corn: cornoides; coru: cornu; cruc: crucifer; cryp: cryptomeres; difd: difformoides; diff: difformis; dist: distinguendus; dulk: dulkeiti; dyki: dyki; erge: ergensi; exte: extensus; falc: falcatus; fall: fallax; fini: finitimus; folk: folkmanovae; form: formosus; frat: fraternus; hemi: hemiamphibothrium; inex: inexpectatus; inte: intermedius; izju: izjumovae; lame: lamellatus; mall: malleus; mino: minor; nano: nanoides; nanu: nanus; parv: parvus; prop: propinquus; pros: prostae; ramu: ramulosus; rari: rarissimus; ruti: rutili; simi: similis; sphy: sphyrna; squa: squameus; tuba: tuba; vast: vastator; vist: vistulae; vran: vranoviensis; wund: wunderi; zand: zandti.
Table 1.
Type I error estimates and their 95% confidence intervals for 0.01 and 0.05 significance levels.
Figure 4.
Statistical power for simulations under Approach 1 (Random links added).
A, B: 10 host-10 parasite simulations; C, D: 20 host-20 parasite simulations. PACo (present study): circles (solid line); HCT [34]: crosses (dotted line); Parafit [7]: triangles (dashed line).
Figure 5.
Statistical power for simulations under Approach 2 (Coevolutionary links replaced).
A, B: 10 host-10 parasite simulations; C, D: 20 host-20 parasite simulations. PACo (present study): circles (solid line); HCT [34]: crosses (dotted line); Parafit [7]: triangles (dashed line).
Figure 6.
Statistical power for simulations under Approach 3 (Partly congruent trees).
A, B: 10 host-10 parasite simulations; C, D: 20 host-20 parasite simulations. PACo (present study): circles (solid line); HCT [34]: crosses (dotted line); Parafit [7]: triangles (dashed line).
Figure 7.
Procrustean superimpostion plot of pocket gophers and chewing lice.
The ordinations of gopher and lice are Principal Correspondence Coordinates of patristic distances. The lice configuration (dots) has been rotated and scaled to fit the gopher ordination (arrow tips). Length of arrows represents the projection of residuals onto the first two axes. See Fig. 6 for species abbreviations.
Figure 8.
Pocket gophers and chewing lice: contributions of individual host-parasite links to the Procrustean fit.
Jacknifed squared residuals (bars) and upper 95% confidence intervals (error bars) resulting from applying PACo to (A) patristic and (B) genetic distances. Asterisks identify links significantly supported (α <0.05) by ParaFitLink1 [7]. To ease comparisons the median squared residual value is shown (dashed line). See Fig. 2 for species abbreviations.
Figure 9.
Fish and Dactylogyrus spp.: contributions of individual host-parasite links to the Procrustean fit.
Jacknifed squared residuals (bars) and upper 95% confidence intervals (error bars) resulting from applying PACo to patristic distances. Results of the ParaFitLink1 analysis [7] for each link are indicated by the bar colour. To ease comparisons the median squared residual value is shown (red dashed line). See Fig. 3 for species abbreviations.