Ticks and tick-borne pathogens can have considerable impacts on the health of livestock, wildlife and people. Knowledge
of tick–host preferences is necessary for both tick and pathogen control. Ticks were historically considered as specialist
parasites, but the range of sampled host species has been limited, infestation intensity has not been included in prior analyses,
and phylogenetic distances between hosts have not been previously considered. We used a large dataset of 35 604
individual collections and two host-specificity indices to assess the specificity of 61 South African tick species, as well
as distinctions between adult and juvenile ticks, for 95 mammalian hosts. When accounting for host phylogeny, most
adult and juvenile ticks behaved as generalists, with juveniles being significantly more generalist than adults. When we
included the intensity of tick infestation, ticks exhibited a wider diversity of specificity in all life stages. Our results
show that ticks of mammals in South Africa tend to behave largely as generalists and that adult ticks are more hostspecific.
More generally, our analysis shows that the incorporation of life-stage differences, infestation intensity and
phylogenetic distances between hosts, as well as the use of more than one specificity index, can all contribute to a
deeper understanding of host–parasite interactions.