Meeting Abstract

P2.62  Wednesday, Jan. 5  Observations on Sexual Reproduction in Lumbriculus variegatus TWEETEN, K.A.*; VANG, C.; St. Catherine University; St. Catherine University katweeten@stkate.edu

Although asexual reproduction of Lumbriculus variegatus through architomy has been extensively described and many variables affecting regeneration have been examined, observations of sexual reproduction in this organism are very limited. While collecting diploid forms of this oligochaete from two natural habitats in Iowa and Minnesota, we observed worms with obvious reproductive structures. To learn more about aspects of sexual reproduction and early development in L. variegatus, worms from the MN habitat were collected weekly from mid-March through early October for two years. The worms were examined microscopically for reproductive structures and their ability to produce cocoons in the laboratory was monitored. About 50% of the worms had visible reproductive organs from April through early-July; by early August this was reduced to about 7%. Cocoon production occurred from mid-April through early August each collection season. Worms produced cocoons for about one week after being brought into the lab. Embryos were viable with almost 100% of eggs developing into worms that emerged from the cocoons. Following cessation of cocoon release, reproductive structures in the worms degenerated over the course of several weeks. Embryos in cocoons that were cut open into a salt solution remained viable and many developed fully outside of the cocoon. Treatment of embryos with an antibody against acetylated alpha-tubulin was used to determine the stage of development at which ciliated sensory structures developed on the prostomium. Some evidence for regenerative ability in developing embryos was obtained. We conclude that having access to sexually reproducing forms of L. variegatus will open up new avenues of research, particularly related to comparative studies on embryonic development and regeneration.