HARBORAGE PREFERENCES OF AMERICAN AND SMOKYBROWN COCKROACHES (DICTYOPTERA, BLATTIDAE) FOR COMMON LANDSCAPE MATERIALS

Harborage preferences of American, Periplaneta americana (L.), and smo ky brown, P. fuliginisa (Serville), cockroaches were determined in lab oratory experiments. None of the potential harborages [juniper branche s, Juniperus horizontalis L.; pine, Pinus taeda L.; straw; soil; rocks ; or grass, Eremochloa ophiuroides (Munro) Hack, thatch] were toxic in continuous exposure tests. None of the harborages were repellent to A merican cockroaches, but in Ebeling choice box tests smokybrown cockro aches were significantly and consistently repelled by dry soil (mean /- SEM, 6.17 +/- 0.68%). Tested with mixed-stage groups, juniper branc hes were preferred to all other potential harborages by all American c ockroach stages. Smokybrown cockroaches also preferred juniper branche s, but significant proportions were also found harboring under pine st raw and rocks. Tested with single stages, small and medium American an d smokybrown cockroach nymphs preferred pine straw rather than juniper indicating an interaction between cockroach stages and harborage sele ction by small and medium nymphs. Even though relative humidity was si gnificantly greater (45.4 +/- 2.2%) under juniper, light intensity was lower (7.9 +/- 3.9 lux) under pine straw. Smaller nymphs selected har borages with smaller interstitial spaces than larger nymphs; pine stra w had the smallest interstices of any of the tested harborage material s. Harborage selection by American and smokybrown cockroaches is media ted by the physical characteristics of the harborage and the presence of conspecifics.