` MIAMI UNIVERSITY The Graduate School Certificate for Approving the Dissertation We hereby approve the Dissertation of Todd D. Levine Candidate for the Degree: Doctor of Philosophy _______________________ David J. Berg, Advisor ________________________ Brian Keane, Reader ________________________ Ann Rypstra, Reader ________________________ Michael J. Vanni, Reader _________________________ R. James Hickey Graduate School Representative i ` ABSTRACT CONSEQUENCES OF LIFE HISTORY VARIATION IN FRESHWATER MUSSELS: DEMOGRAPHY AND HOST RELATIONSHIPS by Todd D. Levine The evolutionary potential of species resides at the population level. Demographic features, selective pressures, and linkages between populations all influence the evolutionary potential and trajectory of species. Because parasite population dynamics are obligately linked to those of their hosts, parasite evolutionary potential may be dictated by interactions with their hosts. Freshwater mussels in the superfamily Unionoidea are unique among parasites, exhibiting very long free-living stages and are the object of conservation efforts. The study of these mussels provides two-fold benefits: conservation of a unique taxon and provision of data from animals that contrast stereotypical parasites. To examine the population dynamics of mussels, I studied Popenaias popeii, a mussel that inhabits desert rivers in the southwestern United States. I studied the demographics of adult mussels using a 10 year mark-and- recapture dataset, with which I examined the interplay between survival and environmental variables. High flows reduced survival, an effect that may be somewhat ameliorated by the use of habitat refuges. My analysis indicates this population is stable, given that their habitat remains suitable. Second, I studied infestation of fishes by P. popeii and contrasted these results with those from laboratory studies. Many more fishes were identified as potential hosts for P. popeii when only laboratory success was used as a criterion for determining whether they were hosts. Natural barriers to infestation likely reduced the total number of individuals and species that could be infested, reflecting a marked difference between the fundamental and realized niches. Natural infestations must overcome many barriers to infestation including immunology, behavior and phenology. Finally, I examined the population genetic structure of two mussels in the genus Quadrula, whose distributions remain relatively intact. Using mtDNA, I analyzed the relationships between populations ranging from Louisiana to Ontario and Manitoba. Quadrula pustulosa exhibited isolation-by-distance, while the relationship between populations of Q. quadrula could not be predicted by the distance between them. Whereas Q. pustulosa had more haplotypes, Q. quadrula had more substitutions between haplotypes, which may indicate that Q. quadrula is an older taxon. Both species had lower genetic diversities in glaciated regions and contained unique variability in the Central Highlands. ii ` CONSEQUENCES OF LIFE HISTORY VARIATION IN FRESHWATER MUSSELS: DEMOGRAPHY AND HOST RELATIONSHIPS A DISSERTATION Submitted to the Faculty of Miami University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Zoology by Todd D. Levine Miami University Oxford, Ohio 2009 Advisor: David J. Berg iii ` Table of Contents Chapter 1: General Introduction ..................................................................................................... 1 Chapter 2: Analysis of 10 years of mark-and-recapture data from a critically endangered species of freshwater mussel, Popenaias popeii ......................................................................................... 7 Introduction ................................................................................................................................. 7 Methods ....................................................................................................................................... 9 Habitat Assessment.................................................................................................................. 9 Mark-and-Recapture ................................................................................................................ 9 Population Size Structure ...................................................................................................... 11 Results ....................................................................................................................................... 12 Mussel Habitat ....................................................................................................................... 12 Population Dynamics ............................................................................................................. 13 Size Structure ......................................................................................................................... 14 Discussion ................................................................................................................................. 15 Habitat use and survival ........................................................................................................ 15 Age structure .......................................................................................................................... 16 Conservation Implications ..................................................................................................... 18 Literature Cited ......................................................................................................................... 20 Chapter 3: Fundamental and realized niche breadth in mussel-host relationships, field studies of the infestation of fishes by Popenaias popeii ............................................................................... 32 Introduction ............................................................................................................................... 32 Methods ..................................................................................................................................... 34 Results ....................................................................................................................................... 35 Fish Abundance ..................................................................................................................... 35 ii ` Infestation Prevalence ............................................................................................................ 36 Infestation Intensity ............................................................................................................... 36 Relative Host Suitability ........................................................................................................ 37 Discussion ................................................................................................................................. 37 Literature Cited ......................................................................................................................... 43 Chapter 4: Comparative phylogeography of two closely related, common mussel species ......... 54 Introduction ............................................................................................................................... 54 Methods ..................................................................................................................................... 57 Collection Sites and Methods ................................................................................................ 57 Sequencing COI mtDNA ....................................................................................................... 57 Results ....................................................................................................................................... 59 Discussion ................................................................................................................................. 61 Phylogeography and Glacial History ..................................................................................... 63 Conservation Implications ..................................................................................................... 64 Literature Cited ......................................................................................................................... 66 Chapter 5: General Conclusion and Synthesis .............................................................................. 82 Literature Cited ...................................................................................................................... 86 Appendices .................................................................................................................................... 91 iii ` List of Tables Table 2-1. All two-population (sites 1 and 2) models .............................................................. 30 Table 2-2. Model results for four-population models .............................................................. 31 Table 3-1. Fishes studied for determination of host status. ......................................................... 47 Table 4-1. Partitioned genetic variation from Analysis of Molecular Variance. .......................... 71 Table 4-2.Summary of differences in genetic structure observed between the two species of Quadrula. .....................................................................................................................................