D3199: Environment and density dependence effects on Rhipicephalus sanguineus population dynamics in residential environments

Early in Rhipicephalus sanguineus infestations in residential environments, there may be periods when ticks have apparently been controlled, as they are in developmental stages and not visible to humans. Later, this breaks down and host-seeking ticks of multiple stages are visible consistently and simultaneously. One hypothesis for changes in population dynamics is variation in residential environments and resulting exposure to different environments during development. Dogs are the primary host for this tick and are thought to be tolerant of high tick burdens, but it is likely there is some level of host-mediated density dependence. An individual-based model was used to explore the consequences of environment and density dependence on population dynamics. Environments were cell based, approximating types of spaces in a residence. Walls and living spaces had constant conditions, while attic and garage spaces fluctuated with attic maximum temperatures higher than garage. Other characteristics, such as dog access and visibility of ticks to humans, varied between cell types. Density dependence included maximum number of ticks feeding on a dog at one time, feeding success dependent on the number of ticks on the dog, and feeding success based on the accumulated number of ticks the dog had experienced. We explored the parameter spaces generated by different combinations of cell types and combinations of density dependent factors. The effects on population growth and persistence and overlap of visible ticks were considered and will be discussed.