Sperm cell development in spider species undergoes in testicular cyst, containing certain number of cells per cyst. As a germ cell matures through entire stages of spermatogenesis, testicular cysts rupture and produced spermatozoa are transferred in a form of cleistosperm. When mature spermatozoa pass through deferent duct, it is known that various types of seminal secretions are released into the lumen to provide auxillary functions to the mature sperms – such as nutrition, protection, or sperm release inside the female body. However, a peculiar type of seminal secretion was observed in this study. In the lumen of deferent duct, encapsulated seminal secretions are observed along with coiled sperm cells. Since the capsule is quite thick – as thick as the one of mature sperm cell, it is thought that the secretion capsule would be transferred as well along with the sperm cells into the spermathecae probably activiating sperm cells through decapsulation. Also, this study revealed that sperm storage in deferent duct occurs in droplet-by-droplet basis; which suggests possible sperm inducing mechanism. Since spider uses pedipalps in copulation to transfer its sperm cells, spider has to fill it accordingly. In other words, stored sperms in deferent duct are released in a droplet at once.

The caddisfly is an aquatic insects that resembles small moth. Silk is produced by the larvae through a pair of labial silk glands. The larvae, caddisworms, use silk not only to produce ‘capture nets’ to collect food particles from the water environment but also to construct ‘silken cases’ for their shelters in running water. Physically, two different processes of silk-producing systems are reported among the different species of arthropod animals: terrestrial and aquatic silk productions. Although both types of silks can be produced along its sophisticated process through a sequential pathway from silk gland, most of our recent knowledges of silk producing system are dependent on those revealed from the terrestrial animals including silkworms or spiders. Therefore, this experiment was initiated to reveal the fine structural aspects of the silk producing system of larval stage of the caddisfly Hydatophylax nigrovittatusu with light and electron microscopes