PARENT SESSION
Oral Session # 59: Mutualism - Parasitism II: Animal and Insect.
Presiding: L Cochran-Stafira
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 203.

Could density dependent engorgement success regulate populations of ticks on Sleepy Lizards?

Tyre, Andrew^{*,1, 2}, Tenhumberg, Brigitte^{1, 2}, Bull, C. Michael ³, ¹ University of Queensland, St. Lucia, QLD, Australia² University of Nebraska-Lincoln, Lincoln, NE³ Flinders University of South Australia, Adelaide, SA, Australia

ABSTRACT- Density dependence in one or more demographic processes is often detected statistically as a relationship between a demographic process and density at small experimental scales. It is not always clear whether or not such a relationship contributes significantly to population regulation at larger scales, especially if the life history is complex and subject to substantial spatial and temporal heterogeneity. Recent reanalysis of population and experimental data on Aponoma hydrosauri, an ectoparasitic tick found on Sleepy Lizards (Tiliqua rugosa) in Australia, suggests that larvae of this tick have reduced engorgement success as numbers of infesting larvae increase. We examined the potential of this process to regulate tick populations at larger spatial and temporal scales in the presence of strong spatial and temporal heterogeneity with an individual based model of tick population dynamics. The results clearly indicate that the observed density dependent relationship is sufficient to regulate the population over long time periods. The model also highlights the importance of understanding the nocturnal refuge use behavior of the host lizards, as this can significantly influence survival rates of life history stages that are waiting for hosts.

Key words: population regulation, parasitism, individual based model