Spatial Density Dependence: Effects of Scale, Host Spatial Pattern and Parasitoid Reproductive Strategy

The parasitoid assemblage of the goldenrod gall moth, Gnorimoschema gallaesolidaginis was studied to determine the efects of scale and host spatial pattern on patterns of parasitism. In the absence of discrete host patches, the relationship between densities of hosts and parasitized hosts was examined on scales of 0.25, 1, 4, and 9-m 2 within and between twenty contiguously sampled 144-m 2 sites. For scales of 1, 4 and 9-m 2 , sample size was held constant by random subsampling of quadrats with replacement. Positive density dependence was detected for total host mortality, host mortality caused by larval and total parasitoid assemblages, and host mortality caused by a solitary parasitoid Eurytoma bolteri, and a polyembryonic parasitoid Copidosoma gelechiae