Host availability modifies climate-based predictions of Hyalomma rufipes distribution with geographically variable...

Hyalomma rufipes is an important African tick vector whose distribution is strongly influenced by climate, but host availability and host-mediated dispersal may modify the spatial expression of climatic suitability. We evaluated these contributions using 1410 unique African occurrence localities and three nested species distribution models: climate only (M1), climate plus host availability (M2), and climate plus host availability and livestock-mobility conductance (M3). Ensemble models were evaluated using 300-km spatial block cross-validation and leave-East-Africa-out geographical transfer, with alternative background designs assessed as a sensitivity analysis. Under spatial validation, M1 showed the highest discrimination (AUC = 0.979; TSS = 0.859), followed by M2 (AUC = 0.975; TSS = 0.833) and M3 (AUC = 0.951; TSS = 0.802). Geographical transferability was substantially weaker, although M3 showed the highest relative transfer AUC (0.659) and the only positive, albeit near-zero, TSS (0.021). Controlled common-sample comparisons showed that host availability substantially modified climate-derived suitability, while livestock mobility produced an additional geographically variable effect, particularly in Kenya. Results were stable across conductance uncertainty scenarios. Overall, climate provided the strongest broad-scale predictive signal, whereas host availability and livestock mobility modified the geography of predicted suitability without improving conventional discrimination metrics. These findings highlight the complementary value of ecological information for interpreting distributions of host-dependent vectors beyond predictive performance alone.