Histology and Morphology of Alimentary Canal of Thrips palmi Karny

  Objective  Histology and morphology of the alimentary canal of Thrips palmi Karny (Thysanoptera: Thripidae), a pest that causes serious damage to its host crops by not only feeding on them but also transmitting viruses, were studied to investigate the infection route of Orthotospovirus on plants.

  Method  Structure of the alimentary canal in T. palmi was examined under the laser scanning confocal microscopy, and the transmission electron microscopy applied for the ultrastructure observation.

  Result  The alimentary canal was shown to consist of foregut, midgut, hindgut, and malpighian tubules. The foregut included pharynx, oesophagus, crop, and cardia. The midgut was made of anterior, middle and posterior parts with no peritrophic membrane. In the anterior midgut, a thin membrane was present on the surface of microvilli. Morphologically, the intestinal wall of posterior midgut had a pleated and a flat side with no membrane on the microvilli surface. The hindgut composed of ileum and rectum. The ileum had strong muscles and a cuticle layer covering the lumen. Inside the rectum, microorganisms seemed to thrive. Four malpighian tubules were located at the junction between the midgut and hindgut extending freely into the hemocoel with numerous vesicles in the cells and abundant microvilli around the irregular-shaped lumen.

  Conclusion  The morphology and functions of the alimentary canal in T. palmi were closely examined to initiate further studies on the pathogenic infection route on crops through the insect.