THE IMPACT OF TICK LOAD ON THE FITNESS OF THEIR LIZARD HOSTS

A survey was conducted of natural populations of the sleepy lizard Til iqua rugosa in South Australia to determine whether infestation by ect oparasitic ticks reduced their fitness. Between 1982 and 1990, 2183 ca ptures of 824 individual lizards were made in an area where they were infested by the tick Aponomma hydrosauri, and 3668 captures of 586 ind ividual lizards were made in an area where they were infested with the tick Amblyomma limbatum. Lizards with high tick loads in one year ten ded to have high loads the next year. Longevity of lizards in the stud y was either not correlated with tick load, or positively correlated. Size achieved was greater amongst lizards with greatest tick load, and lizards in mating pairs had higher tick loads than those never found in pairs. The data do not support the hypothesis that tick load dimini shes host fitness.