Research

My research is both basic and applied. On the basic end of the spectrum, my interests are primarily in understanding ectosymbioses among bark and ambrosia beetles and fungi. These associations range from mutualistic to commensal to antagonisitic, and from facultative to obligate. Some fungi are highly specific and found only in association with a single beetle species, while others can be associated with many beetle hosts. In addition, most of these symbioses are multipartite, with the host beetle associated with two or more consistent partners. Mycangia, structures of the beetle integument that function in fungal transport, have evolved numerous times in the Scolytinae. The evolution of such complex specialized structures indicates a high degree of dependence of the beetles on their fungal partners and the fungi on their beetle partners. Unfortunately, the processes that have shaped current day beetle-fungus symbioses remain only poorly understood. Because many of these associations are multipartite, it is particularly difficult to determine origins of the partners and to detect the most critical factors shaping present day symbioses. Phylogeny, the degree and type of dependence on partners, mode of transmission (vertical vs. horizontal) of symbionts, effects of the abiotic environment, and interactions among symbionts and among symbionts and other members of the biotic community have all played important roles in determining the composition, fidelity, and longevity of associations between beetles and their fungal associates. In my research, I strive to determine how evolution and ecological processes have likely acted in concert to shape these fascinating, complex symbioses.

On the applied end of the spectrum, my research focuses on bark beetle ecology in relation to fire, stand structure, forest restoration and climate change. It also has recently expanded to investigate causes behind massive die-offs of trees across the globe including whitebark pine in North America and the giant Euphorbia tree in southern Africa.