AvTDdiff and VarTDdiff for all five taxa showed significant depth x latitude interactions (Fig. 7 & 8, GAM, p<0.05 for all).
To further investigate depth x latitude interactions, we established five depth zones based primarily on the AvTD patterns in Figure 2: 50–150 m, 151 300 m, 301 600 m, 600 900 m, 900 1220 m.
To more specifically examine how AvTD and VarTD were related to latitude at particular depths (and vice versa), and to more fully investigate significant depth x latitude interactions (see Results), we conducted a second round of GAM (identity link, Gaussian distribution) analyses in which we binned data either by depth or by latitude zones.
These host-pathogen interactions cannot be reliably extrapolated from known lower latitude interactions of related species.
Additionally, 10 of the 11 significant range effects in the full model also showed significant effects of latitude (including interactions with latitude), confirming a strong inter-dependence between range and latitude effects (Appendix C).
As body mass and BMR were significantly influenced by a latitude-sex interaction in the initial analyses of variance (logBM: F = 3.13, p = 0.046, logBMR: F = 3.41, p = 0.035, Additional file 7: Figure S2), further tests were performed separately within sexes.
We review examples of adaptations of arctic host - pathogen interactions and general features to identify major gaps in our knowledge of high latitude host-pathogen interaction.
Results from a recent study [18] demonstrate that landscape, latitude and their interaction affected male adult flight morphology.
The latitude x landscape interaction effect was not significant, i.e. population differentiation varied in a similar way along the latitudinal cline for both landscapes.
