Ultrastructure of sex-pheromone gland cells and cuticle before and during release of pheromone in female eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae)

Abstract

The sex-pheromone-producing gland of Choristoneura fumiferana, as in other moths, is a modified intersegmental membrane between the eighth and ninth abdominal segments. Gland cells differ from epidermal cells in unmodified intersegmental membranes in their size, shape, and structure. One to 2 days before emergence of the adult, the gland cells have few microvilli and the cytoplasm contains mainly rough endoplasmic reticulum. By 1 h before emergence, the cells have the adult characteristics. The basal region below the nucleus contains Golgi complexes, lipid droplets, glycogen deposits, and rough endoplasmic reticulum. The apical region contains many microbodies and extensive smooth tubular endoplasmic reticulum. The apical surface has numerous well-developed microvilli, each of which contains a core of smooth endoplasmic reticulum. In contrast to gland cells, unmodified epidermal cells only contain rough endoplasmic reticulum and their apical projections are small and ill-defined. Cuticle of the gland and unmodified intersegmental membrane does not change after deposition but continues to resemble that of the developing gland 1 to 2 days before emergence. Pore canals are present as gaps in the endocuticle and follow the helicoidal arrangement of the microfibrils. Near the microvilli the pore canals contain a filamentous structure which is replaced by epicuticular filaments near the first lamella of the endocuticle. Groups of epicuticular filaments terminate at an oval depression in the dense epicuticle. Each oval depression opens at the surface of the inner cuticulin. Epicuticular filaments are not the immediate precursors of the pheromone. The probable role of the epicuticular filaments in pheromone synthesis and release is discussed.

Structure and function of the arolium of Mantophasmatodea (Insecta)

“…In addition, the more or less rounded, electron dense secretion vesicles of various sizes that were found within the gland cells are probably filled with proteinaceous material (especially in combination with abundant RER; Quennedey, 1998). Smooth endoplasmic reticulum, which is often found in defensive glands that produce nonproteinaceous secretions (Happ et al, 1966;Crossley and Waterhouse, 1969;Schumacher, 1971;Araujo and Pasteels, 1985), scent glands of Lepidoptera (Percy, 1974;Percy-Cunningham and MacDonald, 1987) and in glands secreting pheromones or lipids (Quennedey, 1972;Cruz-Landim et al, 2005), is apparently absent in the arolium gland cells of K. biedouwense. However, the chemical composition of the secretion remains to be investigated.…”

Ultrastructural study of tergal and posterior sternal glands in Prorhinotermes simplex (Isoptera: Rhinotermitidae)

“…The high amount of SER in the tergal gland cells is in agreement with other observation on pheromone producing glands. SER is a common organelle involved in the production of small, non-proteinaceous molecules (such as lipidic substances, hydrocarbons or quinones), and its absence in pheromone producing organs is rather an exception (Eisner et al, 1964;Percy, 1974;LalanneCassou et al, 1977;Billen, 1987;Vinson, 1994;Sánchez et al, 1998;Wenseleers et al, 1998;Billen et al, 1999;2000; reviewed by Percy-Cunningham & MacDonald, 1987;Tillman et al, 1999). Male secretory cells class 2 may provide lipidic substances serving as a substratum for further steps of biosynthesis in the cells class 1.…”

Ultrastructural aspects of the mandibular gland of Melipona bicolor Lepeletier, 1836 (Hymenoptera: Apidae, Meliponini) in the castes

“…Also, the secretion present in the cells was different: membrane bounded granules of medium electron-density homogeneous content were present in workers and virgin queens, and granules with associated multi-lamellar envelopes in the physogastric queen. These structures were found in gland cells related with defense in Coleoptera (Araujo and Pasteels, 1985) and Lepidoptera (Crossley and Waterhouse, 1969), in the scent glands of Lepidoptera (Percy, 1974) and in pheromone producing glands of Isoptera (Quennedey, 1971) and Hymenoptera (Ribeiro, 2000;Salles and Gracioli, 2002).…”