Rhodnius prolixus is an important vector of Trypanosoma cruzi, the etiological agent of Chagas disease. Insect adults have a pair of Metasternal Glands (MGs) and the secretion emitted by these glands acts as sex pheromone. Recent studies have focused on the chemical composition of this pheromone, electrophysiological responses to MGs compounds and mating behavior assays. Morphological studies of these glands are still scarce. Thus, considering the relevance of MGs in the sex pheromone biosynthesis, we investigated the morphology and ultrastructure of R. prolixus MGs. The glandular apparatus presents a tubular structure containing secretory cells with canalicules that fuse with the central duct which conducts the secretion to a pear-shaped reservoir connected to the exterior by a droplet-shape orifice. The secretory cells are classified as class III, they present a well-developed rough and smooth endoplasmic reticulum. Smooth endoplasmic reticulum is a site of lipid biosynthesis that may be involved in the mevalonate pathway, a probable route of the sex pheromone biosynthesis in this insect. The presence of rough endoplasmic reticulum indicates a possible peptides/proteins secretions site which were still not characterized in MGs. Several mitochondria are scattered in the cytoplasm that may suggest a high metabolic activity. Further studies should be carried out to correlate these data with the sex pheromone biosynthesis in this vector.

Rhodnius prolixus是锥虫（恰加斯病的病原体）的重要载体。成虫有一对后胸骨 (MGs)，这些腺体发出的分泌物充当性信息素。最近的研究集中在这种信息素的化学成分、对 MGs 化合物的电生理反应和交配行为分析。这些腺体的形态学研究仍然很少。因此，考虑到 MGs 在性信息素生物合成中的相关性，我们研究了R. prolixus的形态和超微结构MG。腺体呈管状结构，含有带有小管的分泌细胞，小管与中央导管融合，中央导管将分泌物引导至通过液滴状孔口与外部相连的梨形蓄水池。分泌细胞被归类为III类，它们呈现出发育良好的粗糙和光滑的内质网。平滑内质网是脂质生物合成的场所，可能与甲羟戊酸途径有关，甲羟戊酸途径是该昆虫性信息素生物合成的可能途径。粗面内质网的存在表明可能的肽/蛋白质分泌位点在 MG 中仍未表征。几个线粒体散布在细胞质中，这可能表明其代谢活动很高。