Dispersion of Marked American Cockroaches from Sewer Manholes in Phoenix, Arizona

Abstract

Summary Movements of the American cockroach, Periplaneta americana, from sewer manholes in Phoenix, Arizona, during the summer of 1953 were studied by a trap, mark, release, and recapture technique using paint or radioactive phosphorus. In two experiments where only the resident manhole populations were marked, very limited emigration was observed; only 4 of 800 marked cockroaches being recovered by intensive trapping in yards, homes, and neighboring manholes. However, when 1200 marked cockroaches were superimposed on a resident manhole population of 300 roaches, 71 tagged individuals were recovered within 15 days: one in a home, 5 in yards, and 65 still in the sewer system at distances up to 350 feet from the release point. This suggests that a sudden increase in population over that of the carrying capacity of the environment may incite emigration from the center of pressure.