2 - Biology and Ultrastructure of Sex Pheromone–Producing Glands

Abstract

This chapter discusses the biology and ultrastructure of sex pheromone-producing glands. A pheromone-producing gland is often located initially during observations of the insect's precopulatory behavior. The gland may appear as a bulbous eversion as in many female Lepidoptera, the female praying mantis, and the male scorpion fly. If there is no obvious eversion, the site may be pinpointed by the rhythmical pumping of certain parts of the body, or by the insect's tendency to rub legs or wings against other parts of the body. Another method of locating the gland is through observation of the response of the recipient and recording of the part of the emitter's body to which the recipient pays particular attention. In many pheromone glands, the epidermal cells are hypertrophied, and the resulting glandular cells are in direct contact with the overlying surface cuticle that is produced by the cells themselves. The pheromone is produced within the cells, transported through the cutucle, and disseminated from the surface of the cuticle. Cells may be cuboidal, columnar, modified columnar, or goblet shaped. The histological features characteristic of these cells include a large nucleus, many vacuoles, and sometimes an apical brush border. Some cells, however, differ very little, histologically, from unmodified cells. Ultrastructural studies reveal that they contain smooth endoplasmic reticulum, lipid spheres, microvilli, or apical folds.