REPRODUCTIVE INTERACTIONS BETWEEN 2 AUSTRALIAN REPTILE TICK SPECIES

In South Australia the two tick species Amblyomma limbatum and Aponomm a hydrosauri share the same common reptile host species, but have allo patric distributions which abut along a narrow parapatric boundary. Re productive interference is a mechanism that has previously been sugges ted could contribute to maintaining the boundary. Populations of each species were established in pens within the range of Aponomma hydrosau ri. Pens held either each species alone, or the two species together. The performance of females in those pens was monitored over 28 months. There was no indication that the proportion of attached females which mated and engorged was reduced by the presence of heterospecifics. Th ere was no indication that the time taken to mate, engorge and detach was any longer in the presence of heterospecifics. The experiment did not support the hypothesis that reproductive interference contributes to maintaining the parapatric boundary. However, Amblyomma limbatum in the pens had a shorter season of reproductive activity, and achieved much smaller numbers of reproductive females. This may inhibit success ful colonization of cooler habitats to the south of its distribution.