9617404 Hart This project will test the hypothesis that dusky-footed woodrats use the fresh leaves of particular plants to control nest-borne ectoparasites. If this proves to be true, it would be the first known case of a mammal using the biocidal substances of a plant as a means of combating nest infestation by blood-sucking ectoparasites such as fleas. In the study population, woodrats place sprigs of freshly gathered bay leaves near the rim of their sleeping nests, and pilot observations suggest that bay leaves are effective in preventing the hatching of flea eggs. They may be effective against flea larvae and adult fleas and against mites and ticks as well. Perhaps stickhouses in areas with bay trees harbor woodrats with fewer fleas and ticks than those in areas devoid of bay or other plants with biocidal properties. These questions will be addressed with a series of observational and experimental studies, including remote monitoring of nest activities with "videostick" cameras, tests of the biocidal properties of plant materials against ectoparasitic insects, experimental manipulation of parasiteload, and measurement of the impact of nest material collection on survival and fitness. Improved understanding of the interactions between woodrats and their ectoparasites is of considerable theoretical interest theoretical interest because of implications for the use of medicinal plants by animals other than humans, and has public health implications as well. This study is also of interest because the relationship between behavior and the exploitation of plants as nest protectants may represent another step in the co-evolution of woodrats and their ectoparasites. Additionally, the ticks of woodrats are an important reservoir of Lyme disease and their fleas are potential vectors of plague. Since woodrats occur in or near many public parks as well as in rural areas, and their large houses attract human attention, they constitute a risk.
