HOST LOCATION BY LARVAE OF THE REPTILE TICK AMBLYOMMA-VIKIRRI (ACARI,IXODIDAE)

The newly described tick Amblyomma vikirri has a narrow host range, be ing found mainly on the Australian lizard, Egernia stokesii and rarely on another lizard, Tiliqua rugosa. Both hosts are in the family Scinc idae. Larvae of A. vikirri were as successful in locating E. stokesii as T. rugosa from a range of release distances between 20 and 120 mm f rom the host. Over this range the proportion of ticks which successful ly located hosts declined and the time taken by successful ticks to lo cate hosts increased with increasing release distance. From 60 mm, lar vae of A. vikirri located four other lizard species from the families Scincidae and Agamidae and two non-living targets as successfully as t hey did E. stokesii. The only evidence that there was any host specifi city in the searching behaviour of larvae of A. vikirri was that A. vi kirri larvae spent less time paused and questing when they were search ing for E. stokesii than when they were searching for T. rugosa. Apono mma hydrosauri, a tick which commonly infests T. rugosa but not E. sto kesii, spent less time paused and questing when it was searching for T . rugosa than when it was searching for E. stokesii. However, the resu lts overall suggest that the narrow host range of A. vikirri cannot be explained by any ability of the larvae of that species to discriminat e between their natural host and other reptile species.