We are conducting long-term studies on how belowground herbivory affects such ecosystem processes as above-ground herbivory, gap formation, vegetational change, and insect diversity. A below-ground complex of six weevils and bark beetles partition the roots of red pine based on microsite and tree physiology. All six species respond to common chemical signals, but vary in preferences for and component ratios. Stereochemistry, and gender-specific responses. Root herbivory and vectoring of phytopathogenic root fungi appears to compromise stem defenses against bark beetles. We are experimenting with methods of protecting red pine stands from losses associated with this complex. A second project involves the interface of root herbivory and invasive species. An introduced complex of five root-feeding weevils is impacting northern hardwood forests. Ongoing research is aimed at quantifying the roles of these insects in fine root turnover. Current investigations include:

• Evaluate role of below-ground herbivory and infection in above-ground stem colonization
• Evaluate connectedness among stands, including movement of root insects, herbivores, predators
• Test relative importance of root herbivory and infection, bark beetles, predators in gap formation
• Evaluate how interaction of below- and above- ground processes affects plant & insect composition

Collaborators: Jun Zhu (UW-Stat), Brian Aukema (CFS, UNBC), J. Reeve (SIU), D. Young (UW-Ent), V. Radeloff (UW-FEM), J. Cummings-Carlson (WI Dept. Nat. Res), E Bonello (OSU-PlPathol), W. Mattson (USFS)

For more, see http://www.entomology.wisc.edu/ltreb/

Selected Publications and Presentations