Spatial Variations in Host Density and the Intensity of Parasitism: Some Empirical Examples

Despite the apparent commonness of parasitoid aggregation in areas of high host density, positive spatial correlations between host density and the intensity of parasitism appear to be uncommon in nature. Negative correlations, and lack of any correlation, have been reported more frequently. Much remains to be learned of these important spatial relationships. They presently lack an unequivocal theoretical explanation, and empirical investigations designed to clarify relationships between searching behavior and spatial variations in the intensity of parasitism have not yet been carried out.