STUDIES ON SITE OF SEX-PHEROMONE PRODUCTION IN COCKROACH, BYROSTRIA-FUMIGATA (BLATTARIA-BLABERIDAE)

A site of production is proposed for the female sex pheromone of the cockroach, B. fumigata (Guerin). The digestive system and the colleterial glands were eliminated as possible sources of the attractant. The hypothesis that the genial atrium plays a major role in pheromone release is supported by a high correlation between the presence of plugs in the atrium and negative pheromone assays. Electrocautery of the epithelial lining of the atrium results in a partial or complete suppression of pheromone production. In pheromone-producing animals the distribution of epithelial cell types within the atrium is remarkably consistent whereas that of the non-producers deviates from this pattern. In producers, columnar epithelium of an actively secretory appearance becomes prominent along the middle of the roof of the genital atrium approximately 2000-2700 .mu.m anterior to the posterior tip of the animal. A smaller group of ventral columnar cells 800-1600 .mu.m anterior to this dorsal area also appears actively secretory. In cauterized non-producers these areas differ, appearing more anteriorly, with fewer, smaller cells.