Spider Ovarioles and Their Attachment

Abstract

Warren (1926) stated he observed spider oocytes free in the coelom outside the ovary between the silk glands and the gut ceca. He believed these oocytes broke their funicular connections to the ovary and that in oviposition they had to migrate through the coelom and somehow break an opening into the distal oviduct and from there pass into the uterus. Apparently he interpreted the peripheral position of oocytes iir ovarioles to mean they were unconnected to ovaries. He did not observe their thin funicular connections. Savory (1928) reported the tenuous funiculi connecting the ovarioles to the ovaries in some spiders, but said they disappeared before oviposition. He further stated that the oocytes were positioned between the intestines and the silk glands in the body, and that oocytes passed single file through a perforation near the junction of the oviduct and the uterus and then passed out of the spider's body. Sadana (1970, 1972) reported the penetration of the ovarian wall by immature oocytes, which came to lie in their maturational peripheral positions attched to the ovary by funiculi. But he disagreed with Savory as to how the oocytes exited the body. Sadana claimed that the ovarian wall became thinner and thinner until large holes appeared and the bundles of oocytes entered the ovarian lumen from the body cavity through these holes. Once in the ovary they passed out of the body through the oviducts. Seitz (1971) tested Warren's claims in his study of vitellogenesis in Cupiennis salei Keys. Seitz claimed that only after the ovariole had broken its connection with the ovary did the oocyte within undergo secondary vitellogenesis. Gowan (1985) found contrary evidence in Lycosa lenta Hentz. In his serial sections, mature oocytes were fully connected to the ovary by very thin ovariole funiculi. He was able to remove a complete ovary with ovarioles still attached from a female in midoviposition, and found a continuous stream of oocytes passing through the ovarian lumen, through the oviducts, and out of the spider's body. The authors propose that spider ovarioles do not break their funicular connections to the ovary before of after secondary vitellogenesis or oviposition. Evidence is presented in support of this view, and an explanation of earlier findings by other authors is suggested. Gravid females of Pardosa, Lycosa, and Misumena spp. were killed with chloroform and their petioli cut. Ovaries and their attached oocytes were dissected from abdomens and placed in safranin stain on slides for squashing. The abdomen from one gravid Pardosa spp. was fixed in alcoholic Bouin's, dehydrated with tetrahydrofuran, and infiltrated and embedded in Paraplast. Sections were cut at 8,um, mounted, and stained with Rapid Mallory Heidenhain polychrome stain (Humason 1972). In addition, Gowan's (1985) original serial sections of Lycosa lenta were searched for connections between mature ovarioles and ovaries. Fig. 1 was taken from these slides. In our microdissections of gravid females, oocytes were seen in ovarioles still attached to the ovaries by funiculi. These ovaries could be removed with ovarioles hanging from them. Large, mature oocytes in ovarioles were frequently so tightly packed in the