Fine Structure of the Ampullate ilk Glands in the Wolf Spider, Pardosa astrigera (Araneae: Lycosidae)

Though the wandering spiders do not produce webs for prey-catching, they have silk producing apparatus. Among the four kinds of silk glands in the wolf spider, Pardosa astrigera, the ampullate one is the most predominant gland in both sexes, and is composed of three functional parts; excretory duct, storage ampulla and convoluted tail regions. The duct is basically composed of three superposed types of layers which are inner cuticles, monolayered epithelial cells and peripheral connective cells. The electron lucent subcuticles which have the functions of water removal and orientation of silk fibers during polymerization are well developed at the anterior region near the spinneret. Whereas the endocuticles which contain two types of banding patterns at the cross section are developed at the rest of the duct region. The secretory silks are synthesized within the glandular epithelial cells of the tail as secretory granules, and then released to the inner cavity of the storage ampulla by the mechanism of apocrine secretion. Most of these secretory vesicles are originated from the rough endoplasmic reticula of the glandular epithelial cells, whereas no Golgi complexes are found in any of the cells which have been examined.