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A molecular assessment of range expansion of the northern or virile crayfish (Orconectes virilis), crayfish-based community co-structure, and phylogeny of crayfish-affiliated symbionts Open Access


Other title
Molecular assessment: crayfish and symbionts
Orconectes virilis
range expansion
Type of item
Degree grantor
University of Alberta
Author or creator
Williams, Bronwyn W.
Supervisor and department
Proctor, Heather (Biological Sciences)
Coltman, David (Biological Sciences)
Examining committee member and department
Yeh, Francis (Renewable Resources)
Sperling, Felix (Biological Sciences)
Proctor, Heather (Biological Sciences)
Rogers, Sean (University of Calgary, Biological Sciences)
Coltman, David (Biological Sciences)
Sullivan, Michael (adjunct, Biological Sciences)
Department of Biological Sciences
Systematics and Evolution
Date accepted
Graduation date
Doctor of Philosophy
Degree level
Geographical limits of a species’ range are determined in part by the environmental tolerances of that species, and also by its past and current ability to colonize new areas. Range shifts are a common occurrence in the evolutionary history of almost all taxa; however, anthropogenically-mediated activities have facilitated rapid changes in the distribution of many species directly (via introduction) or indirectly (via alteration in habitat or environment). Identification of the pathways underlying range expansion is critical if we are to understand the ecological and evolutionary potential of a species facing changing abiotic and biotic factors. The northern crayfish, Orconectes virilis (Hagen), has rapidly expanded its western range edge along several rivers in the prairies of North America. Although the spatial extent and timing of spread appear to indicate that the species has responded to a large-scale change in environmental conditions, several lines of evidence suggested that human-mediated introduction may also have played a role in range expansion of the species. The species is currently contiguously distributed along rivers across the Interior Plains, but is also found in several lakes and waterways disjunct from the core range. In this thesis I use phylogeographic analysis to identify two genetically distinct O. virilis haplogroups in the region. One haplogroup is spatially and genetically consistent with patterns expected from gradual post-glacial expansion; however, the second is suggestive of frequent and widespread introduction. I developed microsatellite markers that allowed me to assess fine-scale intra-river genetic patterns associated with spread of O. virilis. I found that genetic patterns were not consistent across rivers, and that recent range expansion has resulted from a combination of natural spread and human-mediated introduction. Two groups of crayfish-associated symbionts were found on O. virilis in the Interior Plains, branchiobdellidan worms and entocytherid ostracods. The distributions of these organisms suggest that factors affecting range limits differ among host and symbionts. Little is known of the ecology and evolution of these symbionts, not only in the Prairies, but also across their global distribution. My examination of phylogenetic patterns of North American branchiobdellidans provides the best supported evolutionary hypothesis of the order to date.
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication
Williams, B.W., H.C. Proctor, and T. Clayton. 2011. Range extension of the northern crayfish, Orconectes virilis (Decapoda, Cambaridae), in the western Prairie Provinces of Canada. Crustaceana 84:451-460.Williams, B.W., C.S. Davis, and D.W. Coltman. 2010. Isolation and characterization of nine polymorphic microsatellite loci in the northern crayfish (Orconectes virilis). Conservation Genetics Resources 2:235-237.Williams, B.W., S.R. Gelder, and H. Proctor. 2009. Distribution and first reports of Branchiobdellida (Annelida: Clitellata) on crayfish in the Prairie Provinces of Canada. Western North American Naturalist 69:119-124.Williams, B.W., K.L. Williams, S.R. Gelder, and H.C. Proctor. 2011. Distribution of Entocytheridae (Crustacea: Ostracoda) in the northern prairies of North America and reports of opportunistic clitellate annelids on crayfish hosts. Western North American Naturalist 71:276-282.

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