The influence of parasites on the retention of long-term partnerships in the Australian sleepy lizard, Tiliqua rugosa.

Many studies have shown that potential partners are less likely to be chosen for mating if they are infected with parasites, although most of those studies have considered short-term choices. This paper shows that the Australian sleepy lizard, Tiliqua rugosa (Scincoidea), retains long-term pair fidelity for up to 21 years. However, in some cases pairs separate, and abandoned males have significantly higher tick loads in their last year with their previous female partner than did males that retained their partners from 1 year to the next.

Temporal and spatial dynamics of a parapatric boundary between two Australian reptile ticks.

Two tick species Aponomma hydrosauri and Amblyomma limbatum that infest large reptiles have an abrupt parapatric boundary near Mt Mary in South Australia. A previous model has suggested that the boundary is maintained at population density troughs resulting from habitat heterogeneity along a gradual environmental gradient. This paper describes the dynamics of the boundary on three transects over 17 years, 1982-98.

Reproductive interactions between two Australian reptile tick species.

In South Australia the two tick species Amblyomma limbatum and Aponomma hydrosauri share the same common reptile host species, but have allopatric distributions which abut along a narrow parapatric boundary. Reproductive interference is a mechanism that has previously been suggested could contribute to maintaining the boundary. Populations of each species were established in pens within the range of Aponomma hydrosauri.

The impact of tick load on the fitness of their lizard hosts.

A survey was conducted of natural populations of the sleepy lizard Tiliqua rugosa in South Australia to determine whether infestation by ectoparasitic ticks reduced their fitness. Between 1982 and 1990, 2183 captures of 824 individual lizards were made in an area where they were infested by the tick Aponomma hydrosauri, and 3668 captures of 586 individual lizards were made in an area where they were infested with the tick Amblyomma limbatum. Lizards with high tick loads in one year tended to have high loads the next year.

No competition for resources between two tick species at their parapatric boundary.

Aponomma hydrosauri and Amblyomma limbatum are tick species with the same major host species, the sleepy lizard Trachydosaurus rugosus, but parapatric distributions in South Australia. Near Mt. Mary one species is abruptly replaced by the other over one kilometre.