Castellanos Nathaly, Martínez Luis C, Silva Eder H, Teodoro Adenir V, Serrão José Eduardo, Oliveira Eugênio E
Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa-MG, Brasil.
Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa-MG, Brasil.
PLoS One. 2017 Jun 28;12(6):e0179478. doi: 10.1371/journal.pone.0179478. eCollection 2017.
The exceptional abilities of stink bugs (Hemiptera: Pentatomidae) to colonize a diverse group of plants have been attributed to the feeding behaviors and the functions of the salivary complex of these insects. Here, we describe the ultrastructure of the salivary glands of the Neotropical brown stink bug, Euschistus heros, which is a major component of the pentatomid pest complex on soybeans, Glycine max, in the neotropics. Our results revealed a salivary gland complex consisting of two lobes (i.e., anterior and posterior), with a constriction between them (i.e., the hilum), in which the salivary and accessory gland ducts are inserted. The principal gland epithelium has a single layer of cells lining an enlarged lumen filled with saliva, and these cells are cuboidal, rich in rough endoplasmic reticulum and secretory vesicles, with well-developed nuclei, all of which are typical features of protein-secreting cells. We report, for the first time in insects, the presence of a layer of muscle cells surrounding the columnar hilum epithelium. The accessory salivary gland cells are cuboidal with nuclei containing condensed chromatin and cytoplasm rich in vacuoles and rough endoplasmic reticulum, indicating the potential involvement of these glands in water transport/secretion. The lumen content of each lobe of the principal gland suggests that the lobes produce different compounds. Thus, our results suggest that the E. heros salivary complex might have unconventional mechanisms to mix/release saliva, which might help explain the polyphagous abilities of these insects.
椿象（半翅目：蝽科）能够在多种不同植物上定殖，其非凡能力归因于这些昆虫的取食行为和唾液复合体的功能。在此，我们描述了新热带褐蝽（Euschistus heros）唾液腺的超微结构，该蝽是新热带地区大豆（Glycine max）上蝽科害虫复合体的主要组成部分。我们的结果显示，唾液腺复合体由两个叶（即前叶和后叶）组成，两叶之间有一个缢缩部位（即腺门），唾液腺导管和副腺导管插入此处。主腺上皮由单层细胞构成，这些细胞排列在充满唾液的扩大管腔内，细胞呈立方形，富含粗面内质网和分泌小泡，细胞核发育良好，所有这些都是蛋白质分泌细胞的典型特征。我们首次在昆虫中报道，在柱状腺门上皮周围存在一层肌肉细胞。副唾液腺细胞呈立方形，细胞核含有凝聚的染色质，细胞质富含液泡和粗面内质网，表明这些腺体可能参与水分运输/分泌。主腺每个叶的管腔内容物表明，不同叶产生不同的化合物。因此，我们的结果表明，新热带褐蝽的唾液复合体可能具有非常规的机制来混合/释放唾液，这可能有助于解释这些昆虫的多食性能力。
