The Bultman Research Lab Group
Research Projects|Collaborators |Current Students|Publications|Past Students|
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Research Projects: Ecology of Invertebrate/Fungal Endophyte Interactions
Dr. Bultman's current research program focuses on the role of endophytic fungi in managed and natural ecosystems and includes three components. Endophytic fungi grow intercellularly within the shoots of many grasses and appear to protect the plants from insect herbivores. The mechanism of this protection is purported to be toxic alkaloids produced by the fungi. His research group has received funging from the National Science Foundation, the U.S. Department of Agriculture and the National Geographic Society.
Wound-Induced Resistance Mediated by Endophytes
One area of investigation in our research group is the hypothesis that grass endophytes mediate wound-induced resistance to insect herbivores. The idea here is that the fungal endophytes might be stimulated to provided heightened levels of protection for the plant following initial damage to the plant. Mediation of induced responses by microbes has not previously been documented, but results in our laboratory suggest it occurs in the grass endophyte system.
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Rhopalosiphum padi aphids on tall fescue demonstrate wound-induced resistance in experiments conducted by students in our laboratory. |
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Intrinsic rate of natural increase [(ln N after 4 days - ln N at initiation)/4 days] of aphids on damaged (by clipping) and undamaged tall fescue with (E+) and without (E-) Neotyphodium infection. F1,96=5.5, p<.05 for interaction term between infection status and damage. |
Multitrophic Interactions
A second area of investigation is the determination of effects of grass endophytes on natural enemies of insect herbivores. If endophytes produce toxic alkaloids, then one might expect that insects feeding on endophyte-infected grasses to be less suitable prey for enemies of the insects. Members of our lab have been investigating this hypothesis in Missouri using tall fescue, fall armyworm, and its parasite, Euplectrus. In addition, work has also been conducted in New Zealand using perennial ryegrass, Argentine stem weevil, and its parasite, Microctonus hyperodae. Questions of herbivore deterrence and multi-trophic effects are currently both being investigated in cultivars of tall fescue with novel endophytes in a collaborative project between his lab and the University of Georgia and workers in New Zealand.
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Microctonus hyperodae parasitizing its host in New Zealand. |
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Index of developmental rate of Microctonus hyperodae when reared from weevils fed perennial ryegrass containing different endophyte strains (F4,211 = 6.55, p < 0.001, histograms with common letters are not significantly different from one another, Tukey's multiple comparison test). |
"Pollination"-like Mutualism Between Fungi and Flies
A third area of work involves the sexual stages of grass endophytes and their interaction with fly visitors. Epichloe spp. are grass endophytes that produce epiphytic fruiting structures on stems of their host. The fruiting bodies produce spores and are self-incompatible. Spores from one fungus must be outcrossed to a fungus of the opposite mating type. The fly, Botanophila spp., provides the service of transporting fungal spores (as it visits the fungi for egg laying), much like many insects pollinate flowering plants. Work has included study at sites in Missouri as well as in southern England and northern Switzerland. Objectives of our work are to: 1) quantify the cost for the fungus of engaging in the mutualism, 2) assess the degree of host specialization by flies, and 3) better understand the coevolution between the partners of this unusual interaction.
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Botanophila fly on a stroma of Epichloe in Zurich, Switzerland. |
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Mean surface area of stromata per fly egg for each study season. Histograms within years with common letters do not differ from one another as shown by Tukey-Kramer multiple comparisions. As up to three eggs were added to fungi the amount of stroma surface area (food resource) per fly egg decreased. |
Five students are beginning work in the Bultman lab this academic year. Seth DeVries (Fishers, IN), Qingfei Jiang (Changchun Jilin, China), Aaron Johnson (Grand Blanc, MI), Mellisa Sulok (South Bend, IN) and Ryan White (Byron Center, MI) are all working on aphid-parasitoid-endophyte interactions.
Dr. James White, Department of Plant Pathology, Rutgers University, New Brunswick, NJ 08903 (http://AESOP.RUTGERS.EDU/~plantpath/)
Dr. White first introduced me to fungal endophytes. We have worked on the Botanophila-Epichloe interaction over the past 15 years. While both at the University of Texas, we documented that the fungus is heterothallic and that Botanophila flies act as "pollinators" for the fungus. Jim is an international authority on endophyte biology and systematics, having published more than 70 articles in scientific journals on the topic.
Dr. Thomas Coudron, ARS-USDA, Biological Control of Insect Research Lab, Columbia, MO 65205-5001 (http://web.missouri.edu/~bcirl/)
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Fall armyworm with larvae of external parasitoids, Euplectrus comstockii. |
Dr. Coudron is a research chemist with interests in parasitoid venums and insect rearing. Tom and I collaborate on multitrophic interactions among plants, herbivores and their enemies and how these are influenced by endophytic fungi. We have shown that the performance of the parasitoids is negatively affected by Neotyphodium endophyte.
Dr. Stanley Faeth, Department of Biology, Arizona State University, Tempe, AZ 85287 (http://ls.la.asu.edu/biology/faculty/faeth.htm)
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Dr. Faeth was my Ph.D. adviser at Arizona State University. He and I have collaborated on work involving leaf-mining insects and the oaks they interact with and, more recently, on the ecology of plant-fungus-insect interactions.
Mr. Mark McNeill and Dr. Stephen Goldson, Biocontrol & Biosecurity, AgResearch, Gerald Street, P.O. Box 60, Lincoln, NEW ZEALAND. (http://www.agresearch.cri.nz/)
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Mark taking a break from sampling weevils. |
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John Proffitt and Simon Kelly, two workers (and awesome circuit trainers!) in the lab I worked in during my sabbatical during 1996-1997. |
The lab in Lincoln is concerned with the control of pest insects, like the Argentine stem weevil. While I was there I investigated the effects Neotyphodium endophytes might have on parasitoids of the weevils.
Dr. Adrian Leuchtmann, Geobotanisches Institut ETH, Zollikerstrasse 107, CH-8008 Zurich, SWITZERLAND (http://www.geobot.umnw.ethz.ch/staff/home/Mycology/Sites/frame.htm)
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Adrian (right) and I exploring an alpine meadow during a pre-excursion visit for his Botany class. |
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Dominik Brem (left) and Tom Peck at meadow near Merishausen. Dominik did his Ph.D. with Dr. Leuchtmann and Tom was a Truman State student who worked with us during the summer of 2000 in Switzerland. |
Dr. Leuchtmann is a molecular evolutionary biologist who works on the systematics and evolution of endophytic fungi. We collaborated on work aimed at determining the degree of specificity of Botanophila flies in host selection during the summer of 2000.
Publications (last 5 Years)
Bultman, T.L. and P.L. Mathews. 1996. Mycophagy by a millipede and its possible impact on an insect-fungus mutualism. Oikos 75: 67-74.
Boning, R.A.* and T.L. Bultman. 1996. A test of consitutive and induced resistance by a grass to an insect herbivore: impact of a fungal endophyte. American Midland Naturalist 136: 328-335.
Bultman T.L., K.L. Borowicz*, R.M. Schneble*, T.A. Coudron, R.J. Crowder*, and L.P. Bush. 1997. Effect of a fungal endophyte and loline alkaloids on the growth and survival of two Euplectrus parasitoids. Oikos 78: 170-176.
Bultman, T.L., J.F. White, Jr., T.I. Bowdish*, and A.M. Welch*. 1998. A new kind of mutualism between insects and fungi. Mycological Research 102: 235-238.
Bultman, T.L. and N.J. Conard*. 1998. Effects of endophytic fungus, nutrient level, and plant damage on performance of fall armyworm (Lepidoptera: Noctuidae). Environmental Entomology 27:631-635.
Bultman, T.L. and J.C. Murphy. 2000. Do fungal endophytes mediate wound-induced resistance? pp. 421-452 In: Bacon, C.W. and J.F. White, Jr. (eds). Microbial Endophytes. Marcel Dekker, Inc., New York, NY.
Bultman, T.L., A.M. Welch*, R.Boning*, and T.I. Bowdish*. 2000. The cost of mutualism in a fly-fungus interaction. Oecologia 124:85-90.
Pawlitz, R.J.* and T.L. Bultman. 2000. Host selection by a mycophagous fly and its impact on fly survival. Ecography 23:41-49.
Bultman, T.L. and G. Bell*. in press. Interaction between fungal endophytes and environmental stressors influences plant resistance to insects. Oikos
Bultman, T.L. and M. McNeill. in press. Genotype-dependent impacts of fungal endophytes in a multitrophic interaction. Oikos
Faeth, S.H. and T.L. Bultman. in press. Endophytes and multitrophic plant-insect interactions. In: T. Tscharntke and B.A. Hawkins (eds.) Multitrophic level interactions. Cambridge University Press, Cambridge, UK.
* - undergraduate student
Past Students (Truman State University)
| Undergraduate Student | Year | Semester | Outcome |
| Sarah Taylor | 89 | Summer* |
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| 89-90 | Academic Year |
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| Lynn Parker | 89 | Summer |
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| Jeffrey Johnston | 90 | Summer |
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| 91 | Summer |
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| Chris Montgomery | 89-90 | Academic Year* |
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| 90 | Summer* |
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| Todd Bowdish | 90-91 | Summer* |
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| 91-92 | Academic Year |
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| Mike Rugge | 91 | Summer* |
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| 91-92 | Academic Year |
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| David Heim | 91-92 | Academic Year |
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| 93 | Summer # |
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| Bob Crowder | 92 | Summer* |
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| 92-93 | Academic Year |
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| Andrea Davis | 92 | Summer # |
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| Allison Welch | 92 | Summer # |
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| 92-93 | Academic Year |
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| Marty Schneble | 93 | Summer # |
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| David Ganey | 93 | Summer |
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| John Thorne | 93-94 | Academic Year |
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| Becky Boning | 94 | Summer $ |
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| Nyree Conard | 94 | Summer # |
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| Barbara Bennett | 94 | Summer # |
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| Kristin Borowicz | 94 | Summer # |
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| Lesli Jenkins | 94-95 | Academic Year |
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| Rachel Pawlitz | 94-95 | Academic Year |
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| 96 | Summer #% |
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| Jennifer Ruder | 94-95 | Academic Year |
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| Cheryl Hightower | 95 | Spring |
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| Lisa Kruse | 95 | Summer # | |
| Jennifer Koslow | 95 | Summer # |
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| Rene Robinson | 96 | Summer $$ | |
| Dawne Parker | 97 | Summer $$ | |
| Sarah Achleitner | 97 | Summer $$ | |
| Tim Geiger | 97 | Academic Year $$ | |
| Jeffrey Leipoltz | 97 | Academic Year $$ |
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| Gregory Bell | 98 | Summer $$ |
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| 98 | Academic Year |
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| Leah Dudley | 98 | Summer + |
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| 98 | Academic Year |
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| Jeffrey Reed | 99 | Summer $$ |
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| Kirk Tonkel | 99 | Summer $$ |
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| 00-01 | Academic Year ^ |
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| Adrian Stone | 99-00 | Academic Year $$ |
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| Wendy Martin | 99-00 | Academic Year |
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| 00 | Summer ^ |
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| Erin Hagen | 99-00 | Academic Year |
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| Troy Rahmig | 99-00 | Academic Year |
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| Tom Peck | 00 | Summer %% |
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| Master's Students | |||
| Chris Montgomery | 90-91 | Academic Year | |
| Pat Mathews | 91 | Summer |
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| 91-93 | Academic Years |
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| John Murphy | 95-97 | Academic Years $$ |
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* - NMSU undergraduate research stipend support
# - supported by NSF-REU program
$ - supported by NSF-RUI grant #1
$$ - supported by NSF-RUI grant #2
% - supported by NGS grant #1
%% - supported by NGS grant #2
+ - supported by McNair Program
^ - supported by USDA grant
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Contact Information
Phone: (616)395-7372
Fax: (616)395-7125
Email: bultmant@hope.edu