Biological Sciences
Mark Dybdahl
Evolutionary Dynamics of Parasitic Infections and Invasive Alien Species
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As an evolutionary ecologist, Dr. Mark Dybdahl’s research projects are related to two main areas. First, he studies how evolution affects the ecology of invasiveness in alien species. Second, he studies the evolution of interactions between parasites and their hosts. His lab uses molecular genetic marker studies, laboratory infection experiments, studies of natural populations, and controlled lab comparisons of distinct genetic lineages to address these main questions.
Dr. Dybdahl is interested in the evolutionary responses and adaptation in helminthes parasites and their intermediate snail hosts. His work examines how this coevolution leads to parasite tracking of host genotypes and local adaptation. Host-parasite coevolution is a leading explanation for the evolution of sexual versus asexual reproduction. What factors maintain sexual reproduction when asexual strains within a species could expand and displace sexuals? His research addresses whether coevolution between parasites and their hosts prevents clonal expansion according to the “Red Queen” hypothesis.
Emerging parasitic diseases often result from geographic range expansion by parasites, or from expansion in the range of hosts that parasites can exploit. Little is known about whether virulence (damage to their host) should be higher or lower in new host populations as parasites expand their current range. Dr. Dybdahl’s current research interests include the role of host-parasite coevolution and local adaptation in parasite emergence.
Dr. Dybdahl also studies the factors underlying the success of invasive alien species. How do species become successful—abundant locally and widespread geographically—in novel environments outside their native range? He is interested in the role of evolutionary changes and ecological responses during invasion of new geographic range. Are invasive alien species successful because they are generalists capable of succeeding in different environments, or because they evolve and adapt specialization to different environments? Dr. Dybdahl is interested in comparing asexual populations, which tend to evolve as generalists, with sexual populations, which have a greater potential to evolve. Another reason for the success of invasive alien species might be the absence of coevolved parasite enemies in their new range. His lab is studying whether the success of alien populations results from evolution of invasive characteristics in the absence of enemies. In general, his work takes an evolutionary approach to studying invasive alien species, a growing ecological and economic problem, and contributes to methods in invasive species management.
Current research interests include the study of invasive populations capable of sexual and asexual reproduction. Dr. Dybdahl is interested in two major invasive alien species causing both economic and ecological harm: a freshwater snail invading rivers in the western U.S., and a marine tunicate that has become widespread along the coasts of the Pacific and New England states.
Contact Information
Mark Dybdahl, Ph.D.
Assistant Professor
School of Biological Sciences
Washington State University
PO Box 644236
Pullman, WA 99164-4236
Telephone: 509-335-7909 or 335-7914
E-mail: dybdahl@wsu.edu
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