Abstract

The temperatures experienced by the ixodid ticks Amblyomma limbatum and Aponomma hydrosauri whilst attached to sleepy lizards, Tiliqua rugosa, were examined to determine whether differences in the body temperature of the host could explain (1) interspecific differences in the feeding and mating sites of ticks on hosts, and/or (2) the position of the tick parapatric boundary near the transition from mallee to non-mallee vegetation. Attached ticks were exposed to temperatures that were related to, but often higher than, ambient temperatures. Ground surface temperature was a better predictor of lizard body temperature than was air temperature. Mean body temperatures of lizards during winter were lower than those in spring, due to lower ambient temperatures, and were consistently below the threshold temperature required to induce mating in both tick species. Low temperature can also explain the cessation of feeding by larval and nymphal ticks on hosts during winter. The selection of feeding and mating sites by ticks could not be attributed to specific temperature requirements because no attachment site was consistently warmer than another. Furthermore, no change in body temperature of the lizards was detected across the tick parapatric boundary.