Former Graduate Students and Postdoctoral Associates


Aaron Adams

Brian Aukema

Celia Boone

Nicole Broderick

Yasmin Cardoza

Chip Codella

Dave Coyle

Becky Hoffman Gray
Becky Hoffman Gray

Kirsten Haberkern

Richard Hofstetter

Mary Jamieson

Todd Johnson

Kendrick Alex
Alex Kendrick

Kier Klepzig and David Hunt

Brian Kopper (left)

Jim Kruse

Andy Lerch

Nathan Havill and
Nadir Erbilgin

Jesse Pfammatter

Renee Pinski

Johnny Uehlman

 Jamie Powell and
Shahla Werner

Archana Vasanthakumar Archana Vasanthakumar

Kimberly Wallin

Melissa Yanek

Former Grad Students and Postdocs of Ken Raffa



Graduate Students


Brian ‘Howie’ Aukema did his MS on applying chemical ecology to biological control of bark beetles. He demonstrated that carefully selected combinations and timing of specific pheromone components reduce inadvertent removal of predators during trap-out, and improve sampling. He collaborated with Prof. Donald Dahlsten at UC-Berkeley. Brian completed a doctorate in entomology on predator-bark beetle interactions, and a MS in Biometry on spruce beetle-fungal interactions in Alaska.  He was awarded the outstanding graduate student award of the Western Forest Insect Work Conference.  He completed a postdoctoral position in Ken, and Allan Carroll. He’s now Associate Professor of Forest Entomology, and McKnight Land-Grant Professor, at the Univ. of Minnesota:; 612-624-1847.  We have several ongoing collaborations on the population dynamics of bark beetles.


Celia Boone conducted her doctoral research on two aspects of bark beetle ecology: how parasitic wasps exploit volatiles from fungal symbionts to locate hosts, and how efficacy of conifer defense chemicals vary with population phase of mountain pine beetle. Her field sites were in Montana and British Columbia.  She collaborated closely with Diana Six, and her paper was honored as the outstanding manuscript of 2008-2009 by Agricultural and Forest Entomology.  She also worked closely with Joerg Bohlmann Biochemistry, UNBC), Allan Carroll (Canadian Forest Service), and Brian Aukema (CFS).  She then did postdoctoral studies with Ken, and Joerg Bohlmann on bark beetle-bacterial interactions.  She worked closely with Cameron Currie (UW-Bact).  Celia is now a Postdoctoral Research Associate at the Univ. Libre de Bruxelles in Belgium.


Nichole Broderick did an independent undergraduate study on the synergism of Btk activity on gypsy moth by an antibiotic. She subsequently completed a MS on the microbial community of the lepidopteran midgut. Nichole’s research was in collaboration with Profs. Jo

Handelsman and Robert Goodman, UW-Plant Pathology. She completed her Ph.D. in Ken’s lab, with a joint major in microbiology under Jo Handelsman, on environmental and developmental factors affecting the midgut flora of Lepidoptera. She was a Postdoctoral Associate at the Global Health Institute in Lausanne, Switzerland, and is now an Assistant Professor at the University of Connecticut.


Sylvio ‘Chip’ Codella conducted his Ph.D. research on factors affecting the ability of sawflies to defend themselves against ant predators using chemicals sequestered from host conifers. He quantified the effects of plant chemistry, larval density & size, and ant responses in determining the outcome of sawfly – ant encounters. He did extensive field work in northwestern Wisconsin.  He was awarded a Sigma Xi grant. He is currently Associate Professor in the Biology Department at Kean College, New Jersey; (908) 527-2464.


Dave Coyle studied the ecology and impacts of invasive root weevils in northern hardwood forests.  He did field work in the Upper Peninsula of Michigan, collaborating with Bill Mattson USDA FS.  He also did studies in the UK, and with the CDC on how interactions between below- and above- ground processes affect black-legged tick populations and Borrelia titres, collaborating with Susan Paskewitz.  He received the ESA Comstock award, ESA Student Activities Award, and awards from the Ecological Society of America and British Ecological Society.  He represented the North Central region at the 2011 North American Forest Insect Work Conference.  An avid basketball player and unapologetic Minnesota Vikings fan, Dave is currently a Postdoctoral Associate at the University of Georgia.


Nadir Erbilgin studied factors associated with declining red pine stands, particularly belowground herbivory, root colonizing fungi and habitat features affecting predator – prey interactions of bark beetles.  Nadir did field work throughout south central and western Wisconsin.  He is now an Associate Professor and Agriculture Canada Chair at the University of Alberta.  He has received several honors there, most notably the Faculty of Agriculture and Life Sciences Research and Innovation Award.  Nadir is at (780) 492- 8693 We have ongoing collaboration on the host range and symbiotic relationships of bark beetles.


Rebecca Hoffman Gray worked as an undergraduate in Ken Raffa’s lab, and then conducted her MS on the population dynamics of gypsy moth.  She investigated the major natural enemies associated with each life stage, how forest habitat affects the performance of these natural enemies.  She conducted her field work in Chequamegon-Nicolet National Forest in northeastern Wisconsin.  Becky is now the Forest health Team Leader for the Wisconsin Dept. Natural Resources. 608-275-3273. We have ongoing collaborations on the population dynamics of gypsy moth and biological control of emerald ash borer. 


Kirsten Haberkern conducted her MS on the guild of beetles and associated fungi colonizing white spruce in the Great Lakes Region.  Kirsten minored in Plant Pathology, and worked closely with Barb Illman in the USDA FS Forest Products Laboratory.   She conducted her field work in Wisconsin, Michigan, Minnesota, and Alaska.  She is currently a high school science teacher in New Jersey.


Nathan Havill conducted his MS on heritable and environmental sources of rapidly induced resistance in Populus, and on ecological aspects of tritrophic interactions. He quantified the net effects of induced resistance on the reproductive fitness of parasitoids, based on both behavioral and developmental components. He then received his doctorate at Yale University. Nathan is now a Research Scientist with the USDA Forest Service in Hamden, CT; phone 203-230-4320.


Richard Hofstetter worked as an undergraduate in Ken lab, then conducted his MS on the behavior and ecology of the egg parasite Ooencyrtus kuvanae. He quantified the roles of wasp density, egg mass size, and host plant species in the orientation, reproductive ecology, and sex ratios of this biological control agent of the gypsy moth.  He was subsequently employed by the USDA ARS in Yakima, WA, and then completed doctoral studies at Dartmouth Univ. in collaboration with the US Forest Service.  He is currently Associate Professor of Forest Entomology at Northern Arizona University. He has received several prestigious awards there, including Researcher of the Year in the School of Forestry, and Most Promising Young School of NAU.  928-523-6452


Todd Johnson studied biological control of an invasive buprestid, the Emerald Ash Borer. He conducted releases of three parasitic wasps, in collaboration with state and federal scientists, and confirmed establishment of one species. This was the first known successful establishment of a natural enemy of this invasive insect in Wisconsin. He used lab olfactometer assays to document sources of volatile attractants for one introduced and one native wasp species. Todd also evaluated the diversity of insect communities associated with native Agrilus in Wisconsin. He gave numerous scientific and outreach presentations. After receiving his MS in our lab, Todd went to the Univ. Illinois for his doctoral studies. Contact:


Alex Kendrick studied the chemical ecology of cottonwood leaf beetles.  He demonstrated that these insects respond to compounds of both beetle and plant origin, and that the attractiveness of plant compounds increases with herbivory.  He also characterized the major natural enemies of cottonwood leaf beetles in hybrid poplar plantations.  Alex did his field work near Alexandria Virginia.  He is currently a professional web designer.


Kier Klepzig did his MS and Ph.D. on interactions among subcortically feeding insects and their associated fungi with conifer defense physiology. He documented effects of belowground herbivory on increased susceptibility to feeding by stem feeding bark beetles, and colonization by phytopathogenic fungi. He received the O.N. Allen Memorial Scholarship awarded by the Phytopathological Society of America and a Sigma Xi grant. Kier conducted his program in collaboration with Gene Smalley, Dept. Plant Path. He is currently Assistant Director of Research for the Southern Research Station in Asheville, NC; Kier has received several honors, including the AD Hopkins Award of the SFIWC. 828-257-4832.   We have several ongoing collaboration on bark beetle – symbiont interactions.


Adam Krause conducted his MS research on predators of mountain pine beetle in high elevation stands. He compared the composition and numerical abundance of predators between whitebark and lodgepole pine stands, in the Greater Yellowstone Ecosystem, in Wyoming and Montana. While in our lab, Adam won the award for outstanding Teaching Assistant in introductory biology. He is pursuing his devoting to education by continuing his advanced degree in Education at UW-Madison.


Steven Krause conducted his Ph.D. research on the role of leaf life history in tree responses to folivory. He described differential responses between larch and pine based on carbon storage patterns. He was awarded a Sigma Xi grant and a co-PI and a USDA Competitive grant. This research was conducted in collaboration with Peter Reich, UW Dept. Forestry. After graduating, Steve served as state gypsy moth coordinator for the Wisconsin Department of Trade & Consumer Protection in Madison from 1990 – 1997, and is now with Valent Inc.


James Kruse conducted his MS on the role of host plants in the developmental success of the larval parasite Cotesia melanoscela. He identified differential responses to host plants between two strains of this biological control agent of the gypsy moth, and quantified the effects of host plant switching on larval parasitism and parasitoid success. He subsequently completed a doctoral program at the University of California – Berkeley, and is now a forest entomologist with the US Forest Service in Lakewood, CO. 907-451-2701;


Andy Lerch completed his MS doing field studies in northeastern Utah on how wildfire influences the responses of ponderosa pine and lodgepole pine to mountain pine beetles, with emphasis on beetle population dynamics. He worked in close collaboration with Barbara Bentz, US Forest Service, who served as Andy’s co-mentor.  He obtained degrees in both Entomology and Forest & Wildlife Ecology. He is now Acquisition Forester, for the Quinault Nation in Washington State.


Charles Mason completed his Ph.D. on bacterial associates of gypsy moth. He demonstrated that bacteria can degrade phenolic glycosides in aspen leaves that are deleterious to gypsy moth larvae. He also characterized the communities of bacteria on aspen leaves, and how these change post ingestion by gypsy moth larvae. After finishing his degrees, Charlie also investigated induced chemical responses in pines to simulated bark beetle attack, an area in which he and Ken have several ongoing collaborations. Charlie is currently a postdoctoral associate at Penn. St. Univ., researching bacterial associates on invasive wood borers. 608-316-5738


Jamie Pfammatter conducted his Ph.D. on phoretic mites associated with bark beetles. He characterized distributions of mites at multiple levels of scale: species-specific location preferences on individual beetles, across regions of Wisconsin, and across the US. He studied cues that elicit mites to detach from beetles and orient within galleries. He showed how feeding on fungal symbionts of bark beetles, but not opportunistic fungal colonizers benefit mite reproduction. Jesse collaborated with several former members of our lab in his studies. He is now a postdoctoral associate in the Medical School at UW-Madison. 847-347-7815.


Renee Pinski conducted her MS on the basic biology and host range of an invasive weevil complex affecting northern hardwood forests.  Renee’s field work was conducted in the Upper Peninsula of Michigan and northern Wisconsin.  Her work was in collaboration with Bill Mattson, USDA FS.  Renee is now a Plant Pest and Disease Specialist with the Wisconsin Department of Agriculture and Trade and Consumer Protection..


Erinn Powell did her MS research on interactions between fire and mountain pine beetle in the Greater Yellowstone Ecosystem.  She studied how beetle behavior, brood production, and tree defense physiology relate, and evaluated how their interactions affect beetle population dynamics.   Erinn worked closely with Monica Turner (UW Zoology) and Phil Townsend (UW Forest and Wildlife Ecology), obtaining degrees in both Entomology and Forest & Wildlife Ecology.  She then worked as a Research Intern in Ken Raffa’s lab:


Jaimie Powell completed a MS on the chemical ecology of conifer – gypsy moth interactions. She quantified the effects of monoterpenes and diterpene acids on gypsy moth, and their distribution within Larix. Jaimie was a WARF Fellow.  She completed a Ph.D. within Ken Raffa’s lab.  Her doctoral research concerned the role of host plant feeding breadth on the relative importance of detoxification, sequestration, and excretion, in contending with plant allelochemicals. She is currently an Instructor and Research Associate at Portland State University.


Lynne Rieske did her MS on the chemical ecology, population sampling, and niche partitioning of pine root weevils. She conducted her Ph.D. on the basic biology of the Introduced Basswood Thrips, and the effects of bud feeding on foliar ethylene emission and subsequent host plant susceptibility to folivores. She was awarded a Sigma Xi grant and a citation of merit from the Association of Women in Science, twice won the Entomological Society of America’s outstanding student presentation, and won the ESA’s Comstock award for outstanding graduate student. She is currently Professor of Forest Entomology at the Dept Ent, Univ. Kentucky, where she has won several awards, including the first woman recipient of the A.D. Hopkins Award for lifetime achievement to southern forest entomology;  859- 257-7457.


Dan Robison did his Ph.D. on the genetics and mechanisms of resistance in hybrid poplar against lepidopteran defoliators. He received a Sigma Xi grant, and was named outstanding graduate student by the Wisconsin Arborists Society. He collaborated with Brent McCown, UW – Horticulture. Dan became Associate Dean for Research, College of Natural Resources, Professor of Forestry, and Director of the Hardwood Silviculture Consortium, and Professor, at North Carolina State Univ. He is now dean of the School of Agriculture, Natural Resources, and Design at West Virginia University.  919-515-2890;


Johnny Uelmen completed his MS investigating how simulated warming will influence phenological synchrony between forest tent caterpillars and their host plants. In this collaborative project with Rick Lindroth, Johnny found that populations vary in their degree day responses, and that both spring treatments and winter conditions affect egg hatch. He also determined the super cooling points of forest tent caterpillar eggs from various sources. Johnny is now furthering his graduate education at UW-Madison, in epidemiology. 920-979-9888,


Shahla Werner did her MS on how forest management practices affect the biodiversity of ground beetles.  Her field work was in remote stands, largely in the Sylvania Wilderness area of the Upper Peninsula of MI.  She did her Ph.D. on the contribution of an invasive thrips to a forest decline.  She identified asynchrony between native predators and exotic thrips as a likely contributing factor.  Shahla was active in EGSA, was co-chairperson of Wisconsin Chapter of NOW for 3 years, and was an Insect Ambassador.  She worked for several years as a Forest Entomologist with the PA Dept. of Conservation & Natural Resources, then as Science Advisor of the John Muir Chapter of Sierra Club in Madison, WI, and is now Plant Pest and Disease Specialist with the WI DNR.


Kimberly Wallin worked first as a student hourly in Ken’s lab, where she worked on genetic aspects of willow resistance to herbivory. She conducted her MS on host – mediated interactions between feeding guilds, specifically the effects of folivory on susceptibility to bark beetles and wood borers. She related these patterns to the chemistry of induced localized defenses in conifers, and to general plant defense theory.  Kimberly completed her doctoral studies on the relationship between individual host selection behavior and population dynamics of eruptive species. She conducted work on spruce beetle in Alaska, Canadian Yukon, and Utah.  She is currently an Associate Professor in the School of Environmental and Natural Resources at the Univ. Vermont: 802-656-2517


Melissa Yanek did her MS on the intersection of endangered and invasive species.  She studied whether virus applied to control gypsy moth affects the Karner Blue Butterfly.  Her field work was in the Driftless Area and Central Sands region of Wisconsin, in oak savannahs.  Melissa coached a girls high school crew team while here, and was very active in our Insect Ambassadors program with K-12 students.  She is currently an Entomologist with Sygenta Inc in North Carolina.


Postdoctoral Research Associates


Aaron Adams conducted postdoctoral research on bacterial symbionts of phloem- and wood- boring insects.  He published papers quantifying the population structural of symbionts of the red turpentine beetle, describing high cellulolytic activity of Actinomycete symbionts of Sirex noctilio, and demonstrating metabolism of pine toxins by symbionts of mountain pine beetle.  Aaron applied his microbiological skills to brewing beer by starting a successful brewpub (Hydro Street Brewing Co).


Brian Aukema did a postdoctoral associate collaboration with the Canadian Forest Service.  He studied the landscape ecology of the mountain pine beetle in British Columbia.  He quantified the relative roles of dispersal and localized reproduction in bark beetle population dynamics, and on the role of various land tenure designations on these factors. Brian was a research scientist with the Canadian Forest Service and an Adjunct Assistant Professor at the University of Northern British Columbia.  He is now Assist Prof. of Forest Entomology, and McKnight Land-Grant Professor, at the Univ. of Minnesota:; 612-624-1847.  We have several ongoing collaborations on the population dynamics of bark beetles.


Yasmin Cardoza studied the roles microbial associates play in the ecology of spruce beetles.  She identified a novel association, in which bark beetles respond to gallery-invading fungi by egesting secretions that contain antibiotic bacteria.  She also identified a novel structure, which she termed ‘nematangia’, in which spruce beetles transport nematodes and yeasts.  Yasmin was hired as an Assistant Professor in the Ent Dept at North Carolina State University, where she became an Associate Professor with tenure. She then became Research Team Leader at Bayer CropScience 352-374-5964.


Italo Delalibera studied the gut bacterial symbionts of wood boring beetles.  He characterized the flora of several bark beetle (southern pine beetle, pine engraver) and cerambycid (Asian Longhorned beetle, Linden borer) species.  He studied compositional changes through the various life stages of Ips pini, and the activity of cellulolytic bacteria in linden borer.  He is currently a Professor at the University of San Paolo.


Kenneth Hobson studied tritrophic chemical signaling. He demonstrated how minor nuances of pheromone stereochemistry and secondary components can allow partial escape while maintaining intraspecific functionality. He became an assistant professor at the School of Forestry, Univ. Canterbury, New Zealand, and is now Museum Curator at the Univ. of Oklahoma Museum of Natural History.


George Hoffman examined the reproductive physiology of pine root weevils, and the role of internal physiology in behavioral responses to host odors. He is now a Faculty Research Associate in the Ent Dept. at Oregon State University, Corvallis.


David Hunt completed a postdoctoral research program on the chemical and nutritional ecology of pine root weevils. He also related weevil trap data to tree damage in Christmas tree plantations. He is currently a Research Entomologist with Agriculture Canada.


Mary Jamieson investigated how anthropogenic increases in global temperature will affect the defense ad nutritional chemistry of aspen and birch leaves for forest tent caterpillar. She conducted a combination of field studies in Minnesota and glasshouse studies in the UW Biotron. She collaborated with several investigators, including Rick Lindroth. Mary is now an Assistant Professor at Oakland University in Michigan. 303-827-4932;


Brian Kopper conducted research on interactions between conifers, bark beetles, and their associated fungi.  He characterized effects of Ophiostomatoid fungi on beetle reproduction across a controlled time course.  He also characterized effects of diterpene acids on fungal germination and growth, and beetle behavior and survival.  Brian is currently an entomologist with USDA AHIS 608-231-9577


Raman Ramachandran quantified the effects of Bt and Bt proteins obtained from genetically engineered E. coli on a variety of lepidopteran and coleopteran defoliators. This work was conducted in collaboration with Brent McCown, UW – Horticulture. Raman is currently a Research Entomologist with Sandoz, Inc. in Bombay, India.


Scott Salom examined the chemical ecology and host selection behavior of pine root weevils. He conducted field behavioral assays using various chemical signals, and also used these lures to study population dynamics.  Scott is currently a Professor in the Ent Department at Virginia Tech, where he has primary emphasis on invasive species. He has received several honors, including the AD Hopkins Award.


Ezra Schwartzberg worked as a postdoctoral associate in a multi-investigator project, at the ‘B4Warmed’ sites in northeastern Minnesota near the Boundary Waters Canoe Area. Collaborators included including Rick Lindroth, Peter Reich, and others. This infrastructure enabled Ezra to manipulate temperatures to emulate those anticipated in the near future in the southern boreal forest. Ezra found that warming advanced both forest tent caterpillar egg hatch and host plant budbreak as expected, but he found that the plants advanced more rapidly. Ezra now runs his own environmental consulting company in the Adirondack Mountains. (518) 253 4112;


Archana Vasanthakumar examined the gut microbiota of phloem and wood- boring beetles.  Using a variety of culture-dependent and molecular methods, she characterized the symbionts of the emerald ash borer and southern pine beetle.  She worked in close collaboration with Jo Handelsman, Plant Pathology, and with Yasmin Cardoza in our lab.  Archana is now a Research Associate at Harvard Univ.


Selected Awards and Recognition to Graduate Students Under Ken Raffa’s Supervision

Name Year Awards and Recognition
Aukema, B. 1999 Entomological Society of Canada Student Research & Training Grant, $1400
Aukema, B. 2001 ESA North Central Branch Graduate Scholarship, $500
Aukema, B. 2001; 2003 ESA President’s Award: Outstanding Student Presentation Runner-up, National Meetings (Sect. Cd4; Ca2,Ce,Cf1)
Aukema, B. 2002 Wisconsin Distinguished Fellowship Award: Louis & Elsa Thomsen Fellowship
Aukema, B. 2003 Western Forest Insect Work Conference Memorial Scholarship
Boone, C. 2009 Environmental Entomology Outstanding Paper Runnerup.
Boone, C. 2010 Agricultural & Forest Entomology Outstanding Paper for 2008 & 2009.
Broderick, N. 2000 NSF-UW K-Infinity Fellowship, $32,400
Broderick P.E.O. 2003 P.E.A. Scholar Award, $8000
Broderick P.E.O. 2006 ESA President’s Award: Outstanding Student Presentation, National Meetings (Sect. C).
Codella, S.G. 1989 Sigma Xi Research Grant, $500; Factors Influencing the Efficacy of Sawfly Chemical Defense
Coyle, D. 2005 Wisconsin Arborists Association Graduate Student Scholarship, $400
Coyle, D. 2006 Applied Ecological Services, $2500
Coyle, D. 2006 EPA Star Grant, $111,516
Coyle, D. 2008 Ent Soc Amer. Student Activities Award, $1000
Coyle, D. 2009 Ent Soc Amer. Outstanding Graduate Student Comstock Award, NCB.
Coyle, D. 2009 British Ecological Society. SEPG Grant. $3800
Erbilgin, N. 1999 UW CALS Travel Fellowship, $200
Hoffman, R. 2005 ESA President’s Award: Outstanding Student Presentation, National Meetings (Sect. C)
Klepzig, K.D. 1991 O.N. Allen Memorial Scholarship, $2,000
Krause , S.C. 1989 Sigma Xi Research Grant, $500; Defoliation-Induced Dynamics of Evergreen and Deciduous Conifers
Krause , S.C. 1989 UW Graduate School Domestic Travel Fellowship, $518; Patterns of Larch Defoliation by Larch Sawflies and Gypsy Moths
Powell, E. 2008 ESA President’s Award: Outstanding Student Presentation Runner-up, National Meetings.
Powell, J. 2000 Ruth Dicke Award, $500
Rieske, L.K. 1988 Sigma Xi Research Grant, $400; Pine Root Weevil complex
Rieske, L.K. 1993; 1994 ESA President’s Award: Outstanding Student Presentation, National Meetings (Sect. C)
Rieske, L.K. 1994 Citation of Merit, Association of Women in Science Educational Foundation, $250
Rieske, L.K. 1995 Entomological Society of America, Outstanding Graduate Student Comstock Award, NCB
Robison, D.J. 1988 Wisconsin Arborists Outstanding Graduate Student, $200
Robison, D.J. 1989 Sigma Xi Research Grant, $400; Forest tent caterpillar: Role of host plant in population dynamics