title: Analysis of large new South African dataset using two host-specificity indices shows generalism in both adult and larval ticks of mammals.
abstract: 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 host-specific. 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.
authors.affiliation: Percy FitzPatrick Institute,DST-NRF Centre of Excellence,University of Cape Town,Private Bag X3,Rondebosch 7701,South Africa.
authors.forename: Marcela P A
authors.identifier: http://orcid.org/0000-0003-0809-4403
authors.initials: MP
authors.lastname: Espinaze
authors.affiliation: Percy FitzPatrick Institute,DST-NRF Centre of Excellence,University of Cape Town,Private Bag X3,Rondebosch 7701,South Africa.
authors.forename: Eléonore
authors.initials: E
authors.lastname: Hellard
authors.affiliation: Department of Veterinary Tropical Diseases,Faculty of Veterinary Science,University of Pretoria,Private Bag X04,Onderstepoort 0110,South Africa.
authors.forename: Ivan G
authors.initials: IG
authors.lastname: Horak
authors.affiliation: Percy FitzPatrick Institute,DST-NRF Centre of Excellence,University of Cape Town,Private Bag X3,Rondebosch 7701,South Africa.
authors.forename: Graeme S
authors.initials: GS
authors.lastname: Cumming
mesh_terms: D000818:Animals; D058507:Host Specificity; D006790:Host-Parasite Interactions; D007814:Larva; D008322:Mammals / Q000145:classification / Q000469:parasitology*; D013019:South Africa; D013984:Tick Infestations / Q000469:parasitology / Q000662:veterinary*; D013987:Ticks / Q000502:physiology*
keywords: Host–parasite interaction; Ixodidae; South Africa; host specificity; ticks