Silk glands and capture nets of Hydropsyche kozhantschikovi Martynov (Trichoptera: Hydropsychidae) larvae

Abstract

Histological studies of the silk glands of the caddisfly larvae of Hydropsyche kozhantschikovi Martynov demonstrated that these structure fold twice into a 'Z' shape with the volume in the center comparatively thicker than in other sections. The glands are more slender towards the mouth and unite with the labium. A pair of muscles, an apodeum between the muscles and the body wall, and a tendon between the muscles and the glands were observed within the thorax. We assumed that silk is spewed through these structures. Examination of the material from the inside of the silk glands showed varying composition. The center was loose and heterogeneous, while the surrounding area was homogeneous. These differences were verified through immunohistochemistry. Scanning electron microscopy show that capture nets of H. kortizantschikovi larvae have randomly arranged silk strands.