The frequency distribution of first generation, Steinernema feltiae Filipjev parasitic stages was over-dispersed with the
majority of hosts containing few or no parasitic stages, whilst a few hosts contained a great many. Because of high extraction
efficiency, the frequency distributions of the parasitic stages and the infective stages in the soil were assumed to be directly
related. To explain the frequency distribution of the parasites it was therefore necessary to account for the frequency
distribution of the S. feltiae infective stages in the soil. The infective stages were spatially aggregated into 30 cm diameter
patches at the site of host death. These patches were randomly distributed approximately 1 m apart. At the 1 m scale, the
pooled counts of infective stages were randomly distributed. Thus, in contrast to the frequency distributions, the spatial
structuring of S. feltiae changed with the spatial scale of the interaction. This dynamic spatial structuring means that the
majority of samples taken would contain few or no infective stages, whilst a few soil samples would contain a great many.
Thus, the spatial structuring of the infective stages generates the over-dispersed frequency distribution of the S. feltiae
in the soil. Hosts, encountering infective stages from this spatial distribution will, therefore, show an over-dispersed
frequency distribution of S. feltiae parasitic stages.