Ultrastructure of male sex pheromone glands in abdominal tergites of five Lutzomyia sandfly species (Diptera: Psychodidae).

The fine structure of male sex pheromone disseminating structures on abdominal segments of five species of Lutzomyia sandflies (Diptera: Psychodidae) was analyzed. Scanning electron microscopy showed that in Lutzomyia cruzi [Mem. Inst. Oswaldo Cruz 33 (1938) 349] and Lutzomyia longipalpis [Mem. Inst. Oswaldo Cruz 4 (1912) 84], the disseminating structures are located in pale spots on abdominal tergites IV or III and IV and are morphologically similar, appearing as small round cuticular elevations with a central pore. Observation of abdominal tergites of L. longipalpis pupae showed that the spots, but not the structures, are already present in this stage. In Lutzomyia lenti [Mem. Inst. Oswaldo Cruz 33 (1938) 349] and Lutzomyia carmelinoi [Mem. Inst. Oswaldo Cruz 81 (1986) 323] adult males, the disseminating structures are present on tergal segments V and VI, where pale spots could not be observed, and appear as apple-like elevations with a central pore. In Lutzomyia renei, a single disseminating structure is found at the anterior region of tergal segment VI. Transmission electron microscopy was used to analyze the gland cell fine structure in L. cruzi. Several class III gland cells are located side by side in the fourth abdominal segment. Each epidermal secretory cell contains a small reservoir and a short outlet channel through the cuticle.