The Influence of Plant Spatial Patterns on Insect Populations

Three different densities of planting were employed in this investigation of the influence of plant spatial patterns on the animal community associated with Brassica oleracea L. (Cruciferae). Plants were spaced at 6 inches, 18 inches, and 9 feet in rows that were, respectively, 6 inches, 36 inches, and 9 feet apart, so that on equivalent areas of 7,500 square feet there were totals of 30,600, 1,768, and 80 plants, respectively. An inverse relationship was found between plant density and the total number of animal taxa present in the various plantings. The proportion of herbivore taxa to carnivore taxa was greatest in the dense planting, least in the dispersed one, but the density of many herbivores in the sparse and dispersed plantings was more than five times that in the dense planting. Plant survival in nature often depends upon a spatial pattern of dense design.