INTERSPECIFIC DIFFERENCES IN MICROHABITAT CHOICE BY 2 SPECIES OF AUSTRALIAN REPTILE TICK

The microhabitat choice of all life cycle stages, both unfed and engor ged, of two Australian ixodid ticks, Amblyomma limbatum and Aponomma h ydrosauri, were compared in the laboratory. When offered a choice betw een bare soil (or sand) and soil covered with litter, most ticks moved into the litter, except unfed larvae which often took refuge within c revices on the surface of exposed sand. The two species differed in th e position they adopted within the litter. Ap. hydrosauri were predomi nately found at the interface between the soil and litter. Amb. limbat um were more often found higher up in the litter. There were also inte rspecific differences in the body orientation of ticks within the litt er. All life cycle stages of Ap. hydrosauri adopted a position with th eir dorsal surface facing upwards, whereas unfed stages of Amb. limbat um were more frequently found with their ventral surface facing upward s. The behaviour of each species probably represents a different compr omise between two factors, maximizing host detection, and minimizing t heir exposure to desiccation or predation.