Spatial distribution of the flower bug,Orius similisand its interaction with the pink bollworm,Pectinophora gossypiellain cotton fields

The distribution of the flower bug, Orius similis Zheng, was examined on cotton plants from the time of bud appearance until the end of harvest. Taylor's power function (Taylor, 1961) and Iwao's patchiness regression (Iwao, 1968) both showed that the population was almost randomly distributed with a slight tendency to aggregation. The coefficients of the patchiness regression indicated that the distributions of flower bugs within the plot could be described by a negative binomial distribution. The spatial association between the flower bug and its prey, the pink bollworm Pectinophora gossypiella Saunders, was investigated using 2 x 2 contingency tables. A statistically significant positive association was found between the two species after the first and second generation peaks of the pink bollworm. By the third generation of pink bollworm, the population of flower bugs was low and there was no longer a statistically significant relationship between the two species. It therefore seems likely that the pink bollworm population in the plot was partly controlled by flower bugs during the first two generations.