General Science

General Science Experts

Robert A Krebs

Biological, Geological and Environmental Sciences
Cleveland State University
United States of America


"My dual interests in biology and chemistry first took me to Virginia Tech, as the only university in Virginia then that offered a degree titled Biochemistry. In time, I pursued questions in WHY organisms behave the way they do, wording that indicated an interest in evolution and speciation. Thus I left chemistry and took a Masters studying morphological evolution and constraints. From there, I followed the famous line of Horace Greeley,'Go West, young man' to research behavioral mechanisms in speciation for a Ph.D. in Arizona, and several research positions: in population divergence and environmental variation in Australia, developmental variation in high temperature tolerance at the University of Aarhus, DK (with field work in the Canary Islands), and eventually the underlying molecular basis of such changes at the University of Chicago. Tempering my westward migration, I came east to Cleveland, where since 1997 I have continued to study the relationship between environmental variation and genetic divergence within species, moving from a model species group, fruit flies, to freshwater mussels. These animals have largely failed to adapt to the changes of urban living, often declining in numbers or disappearing completely. Understanding their tolerance limits to diverse stresses in rivers and lakes is a critical step to initiate recovery, and also one necessary to understand the population biology of this enigmatic family of mollusks."

Research Interest

My research interests have moved from a long history of work on the underlying physiological and ecological causes of population divergence primarily in Drosophila as a model organism, to an examination of the response of freshwater mussels in the family Unionidae to the many stresses imposed by urbanization and agriculture.Loss of unionid mussels became a state and national wildlife concern. Within the Lake Erie watershed, populations in the numerous small rivers flowing to the lake are largely isolated, as the introduction of zebra and quagga mussels (family Dreissinidae) decimated native mussel populations. Currently, water quality is improving, providing an unusual opportunity to track migration and gene flow as species recolonize habitat within watersheds. These studies occur at a local and regional level, aided by collaboration with Dave Zanatta of Central Michigan, with whom an extensive survey of the lower Great Lakes now presents an ecological history of this taxonomic group in and around Lake Erie.


  • Krebs RA (1994) Effects of short-term thermal extremes on fitness components in D. melanogaster. J Evolutionary Biology 7: 39-49

  • Krebs RA (1989) Courtship behavior and control of reproductive isolation in Drosophila mojavensis. Evolution 43: 908-913

  • Krebs RA (1988) The mating behavior of Papilio glaucus: Papilionidae. J Research Lepidoptera 26: 27-31

Global Experts from United States of America

Global Experts in Subject