Research Interests

Evolutionary ecology with specific interests on host-race formation and sympatric speciation in herbivorous insects; fire-induced plant responses; and landscape management and ecology. My laboratory uses a strong quantitative approach through field, laboratory, and greenhouse experiments.

• Plant-insect interactions of three-trophic level interactions using the goldenrod, ball gall inducer, and natural enemies model system.
  Specific studies focus on herbivore impacts on host plants, evolution of plant defense (resistance and tolerance) against herbivores, evolution of insect traits, adult oviposition preference and offspring performance, and host-race formation & sympatric speciation. See also the Solidago/Eurosta and natural enemies web page.
  
  

  A developing gall on tall goldenrod (Solidago altissima) induced by the goldenrod ball gall fly (Eurosta solidaginis). Tall goldenrod typically has dense trichomes along its stem and consequently on its galls. Abrahamson's lab began studying the interactions of this plant and herbivore in the early 1970s (photo by W. Abrahamson).	A female goldenrod ball gall fly (Eurosta solidaginis) on the bud of tall goldenrod (Solidago altissima). Abrahamson's research group is examining the interactions of this herbivore with its natural enemies as well as this herbivore's host-race formation and possible sympatric speciation (photo by W. Abrahamson).
  Abrahamson's research laboratory uses the David Burpee Research Greenhouse at the western edge of the Bucknell University campus and Biology's rooftop research greenhouse facility http://www.bucknell.edu/x766.xml (photo by W. Abrahamson).	Common research gardens adjacent to the Burpee Research Greenhouse enable study of replicated genotypes of goldenrod host plants (photo by W. Abrahamson).
  A ball gall on late goldenrod (Solidago gigantea) induced by a host race of the goldenrod ball gall fly (Eurosta solidaginis). Late goldenrod lacks trichomes on its stem and consequently its gall is glabrous. Abrahamson's lab is actively studying the mechanisms of sympatric speciation via host-race formation in this herbivore and its inquiline tumbling flower beetle, Mordellistena convicta (photo by W. Abrahamson).	Biology's roof-top research greenhouse provides space for experiments with goldenrods, herbivorous insects, and natural enemies including the beetle Mordellistena convicta and parasitoid wasps Eurytoma obtusiventis and Eurytoma gigantea http://www.bucknell.edu/x766.xml (photo by W. Abrahamson).

  
  
• Plant-insect associations of oaks and cynipid wasp gall inducers, particularly host-race formation and speciation.
  
  

  A bud gall on myrtle oak (Quercus myrtifolia) induced by a proposed new species of cynipid wasp, Amphibolips archboldi Melika and Abrahamson. Cynipid wasp/oak interactions may facilitate detailed studies of insect speciation as influenced by their host-plants (photo by W. Abrahamson).

  György Csóka of the Hungarian Forest Research Institute, Warren "abe" Abrahamson of Bucknell University, and George Melika of the Systematic Parasitoid Laboratory, Koszeg, Hungary (left to right) work on the relationships of gall-inducing cynipid wasps and their oak hosts (photo by C. Abrahamson).

  
  
• Ecology of fire and plant demography in Florida's upland communities including scrub, sandhill, scrubby flatwoods, and flatwoods. Long-term studies have explored the demography of two dwarf palms, Serenoa repens and Sabal etonia.
  

  A prescribed burn at the Archbold Biological Station, Lake Placid, Florida. Abrahamson and his students have studied the effects of fire on upland vegetation and two dwarf palms (Sabal etonia and Serenoa repens) since the 1970s.

  Warren "abe" Abrahamson, Stephen Anderson, Ken McCrea, and Stephanie Gebauer perform a nearest-neighbor analysis on two dwarf palms (Sabal etonia and Serenoa repens) in a cutthroat-grass flatwoods at the Archbold Biological Station, Lake Placid, Florida (photo by W. Abrahamson).

  
  
• Conservation studies of central Pennsylvania natural areas including Montandon Marsh, Dales Ridge, Snyder-Middleswarth State Park, and Mohn Mill Ponds.
  
  

  The vegetation patterns of the uplands and wetlands of the Montandon Marsh wetlands complex are a continuing interest of the Abrahamson Research Group. The wetlands complex contains an excellent example of a freshwater marsh, hardwood swamp, and sand dune uplands. Current studies are focused on the restoration of wetlands created by sand and gravel mining (photo by W. Abrahamson).

  An aerial photograph of Dales Ridge, a synclinal limestone ridge, just west of Lewisburg. Pennsylvania. This natural area has hosted studies of several of Abrahamson's students. A conservation easement held by the Merrill Linn Land & Waterways Conservancy protects the study area and provides an hiking trail just a few miles from the Bucknell University campus (photo by W. Abrahamson & Clyde Peeling). The Abrahamson Lab also conducts research on community and population vegetation patterns at other significant regional natural areas including Snyder-Middleswarth State Park "Tall Timbers" and the Mohn Mill Natural Area.

  
  

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