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Dr Stephen C. WeeksProfessorOffice: ASEC 581
Email: scw
Phone: 330 972 7156
Lab Website |
Research InterestsI have long been interested in the evolution mating systems, working with both branchiopod crustaceans and livebearing fish. Currently, my research has focused on delineating the factors allowing the coexistence of male and hermaphrodite (termed "androdioecy") freshwater shrimp in ponds across the world. Over the years of studying this question, my research has evolved into an interdisciplinary (or "integrative") set of projects that combine to approach the complex question of how mating systems have evolved in these shrimp. Several graduate students and I are studying a variety of ecological and genetic aspects of the unique mating system found in these shrimp seeking to discern the costs and benefits of selfing vs. outcrossing in this interesting system. Since this early work, we have expanded to study mating system evolution across the family Limnadiidae using phylogeographic, ecological, behavioral, and genetic approaches. We recently published a paper establishing that shrimp in the genus Eulimnadia have reproduced via androdioecy for 24-180 million years, which is orders of magnitude longer than predicted by models of this mating system and the only system in which androdioecy is known to be this long-lived. We also published a recent review outlining the various androdioecious animals described to date, and noted that our clam shrimp are the most specious taxon known that is entirely androdioecious. We are now pursuing another dimension to this research which will add a paleontological aspect to our comparisons. We have teamed up with Dr. Lisa Park (UA Geology Dept.) to begin to explore our ability to assess mating system type using fossilized carapaces of Limnadiidae. If we can reliably ascertain mating system from the fossil record, we will then open a broad range of research possibilities that would allow us to explore associations of mating system with habitat characteristics over broad time spans. Education1986-91 PhD - Ecology, Rutgers University
1983-86 MA - Biology, University of California, Riverside
1979-83 BA - Aquatic Biology, University of California, Santa Barbara
Selected PublicationsWeeks SC, TF Sanderson, M Zofkova, and B Knott. Breeding systems in the clam shrimp family Limnadiidae. Invertebrate Biology (in press).
Weeks SC and C Benvenuto. 2008. Mate guarding in the androdioecious clam shrimp Eulimnadia texana: male assessment of hermaphrodite receptivity. Ethology 114:64-74.
Weeks SC, C Benvenuto, and SK Reed. 2006. When males and hermaphrodites coexist: A review of androdioecy in animals. Integrative and Comparative Biology 46:449-464.
Weeks SC, TF Sanderson, SK Reed, M Zofkova, B Knott, U Balaraman, G Pereira, DM Senyo, WR Hoeh. 2006. Ancient Androdioecy in the Freshwater Crustacean Eulimnadia. Proceedings of the Royal Society of London, Series B 273:725-734.
Weeks, SC. 2004. Seven generations of inbreeding does not purge inbreeding depression in the clam shrimp, Eulimnadia texana. Journal of Evolutionary Biology 17:475-484.
Hollenbeck, VG, SC Weeks, W Gould, and N Zucker. 2002. Maintenance of androdioecy in the freshwater shrimp Eulimnadia texana: Sexual encounter rates and outcrossing success. Behavioral Ecology 13:561-570.
Weeks, SC, BR Crosser, B Bennett, MM Gray, and N Zucker. 2000. Maintenance of androdioecy in the freshwater shrimp, Eulimnadia texana: Variation in inbreeding depression between two populations. Evolution 54:878-887.
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