#65-86 Lizard Malaria Host Parasite Ecology
Anne Vardo-Zalik, Dept. of Biology, Penn State University-York
Malaria parasites infect a broad range of vertebrate hosts, including mammals (four species infect humans), birds, and reptiles. Since 1978, studies of Plasmodium mexicanum
in the western fence lizard, Sceloporus occidentalis
have greatly advanced the understanding of these parasites. An overall goal is to understand the ecology and evolution of the life history of the parasite, which can serve as a model for the evolution of parasite virulence. Current questions under investigation include: Do infected lizards have different white blood cell profiles than non-infected lizards? Are certain parasite genotypes transmitted more readily than others by the intermediate hosts, two species of sand flies? One species of sand fly is much more common than the other at Hopland, but does the species composition change over time?
#80-11 The Community Ecology of Viral Pathogens: Causes and Consequences of Coinfection in Hosts
Cheryl Briggs, Dept. of Ecology, Evolution, and Marine Biology, UC Santa Barbara
Charles Mitchell, Dept. of Biology, University of North Carolina
This field study, using native and introduced grasses, viruses that infect the plants, and aphids that vector the disease, models factors that control the risk, severity, and incidence of epidemics. Specifically, cereal and barley yellow dwarf viruses are vectored by the aphid Rhopalosiphum padi
to plots of annual and perennial grasses. Intensive field observations monitor and document changes in aphid populations as well as the spatial structure and genetic diversity of the various replicated grass plots that have been established at Hopland. Data are being used to create and manipulate mathematical models in order to evaluate the longer-term dynamic consequences of viral coinfections in a broader range of species.