MICROHABITAT CHOICE AND ITS ROLE IN DETERMINING THE DISTRIBUTION OF THE REPTILE TICK AMBLYOMMA-VIKIRRI

A newly described tick species, Amblyomma vikirri, infests two lizard species in the Flinders Ranges of South Australia. Although one of the hosts, Tiliqua rugosa, has a wide distribution, the tick distribution is restricted to a subset of rocky habitats where the other host, Ege rnia stokesii, lives. Experiments were conducted with unfed ticks, the stage when the tick is waiting for a host and is susceptible to desic cation. Amblyomma vikirri had a significantly stronger preference for rock microhabitats than two other tick species (Aponomma hydrosauri an d Amblyomma limbatum) that infest T. rugosa. Unfed Amb. vikirri were a lso more active than the other two species, and more likely to be in t he upper part of the substrate. At warm temperatures, larvae of Amb. v ikirri survived for shorter periods under desiccation stress than larv ae of the other two species, although as nymphs Amb. vikirri survived as well of better. The rock crevice microhabitat experienced lower max imum temperatures than other potential, non-rock refuge sites. The beh aviour of Amb. vikirri, its susceptibility to desiccation in the larva l stage and the relatively benign conditions in the rock crevices may act together to prevent Amb. vikirri establishing populations beyond r ock habitat.