Premating Reproductive Isolation between Geographically Isolated Populations of an Australian Reptile Tick

Abstract

When males and females from geographically isolated populations of the ixodid reptile tick A. hydrosauri were placed together on the same host [lizard] the normal male searching activity was not observed, and females were not mated. This was attributed to a difference in an excitant signal produced by females. Once males were moving, they were attracted equally to females from either isolate, but courtship did not proceed normally between populations because females did not respond to foreign males. The copulation position taken up by males differed between the 2 isolates. The development of differences in mating behavior between morphologically undifferentiated populations in A. hydrosauri appears to be unique among both argasid and ixodid ticks, where intermating even between different species and genera were reported.