MODEL FOR ESTIMATING RELATIVE ABUNDANCE OF PERIPLANETA-FULIGINOSA (DICTYOPTERA, BLATTIDAE) BY USING HOUSE AND LANDSCAPE CHARACTERISTICS

The relationship between smokybrown cockroach, Periplaneta fuliginosa (Serville), abundance and habitat was quantified using canonical corre lation. Cockroach habitat was described, using 18 house and landscape characteristics based on a sample of 60 homes. Cockroach abundance, es timated by three monthly mean trap catches at each home, was correlate d with habitat. After preliminary analysis, only 11 of the house and l andscape characteristics were retained in the model. No characteristic s dominated the description of habitat (an index) but some contributed positively and others negatively. The characteristics having tile lar gest standardized weights in the habitat index were percentage of lot occupied by home, tree density, number of pets, number of residents, c hemical pest control, age of house, and obvious cockroach harborages o n the property. Unbiased estimates of variables weights of the habitat index obtained by the Jackknife method demonstrated the fit of the mo del and revealed minimal effect of outliers; of 14 weights, 11 had sta ndard deviations <20% of the mean. We predicted that cumulative cockro ach abundance would increase linearly with cockroach habitat index. Re gressions of a control data set (n = 44) and a validation data set (n = 16) both produced positive slopes and, in addition, neither slopes n or intercepts were significantly different between these two data sets . These results validated the correlation model and indicated that it is applicable to all homes in Auburn, not just those in the control da ta set. Use of untransformed data produced similar results and showed that a cockroach habitat index may be used readily by pest control ope rators or homeowners.