Associations Between Parasitic Blow Flies And The Breeding Density And Synchrony Of Cavity Nesting Passerines

Understanding transmission dynamics of parasites can assist in both disease control and conservation. Parasite load is traditionally viewed as a function of host density, but this model fails in some instances, usually depending on the life cycle of the parasite. I examined parasite-host dynamics of two cavity nesting passerines and ectoparasites in the genus Protocalliphora using both spatial and temporal parameters. Parasite load was expected to increase with host density. Parasite load was also expected to differ between time intervals. Host density showed no significant influence on parasite load. Parasite load was significantly in early-season nests than in mid-season nests. Parasite load differed significantly between host species, but not between field sites. This study supports the idea that the transmission of parasites with a life cycle in which adults can disperse independently of the host is only loosely related or entirely uncoupled from host density.