Research in my lab addresses questions in disease ecology, spatial ecology, population genetics, animal behavior and conservation biology. These disparate projects, however, are united by a common theme: the use of mathematical models to answer ecological and evolutionary questions. I am therefore open to any students who are interested in the application of theory in ecology and evolution, irrespective of what organisms they wish to study or of the particular questions that they wish to ask. Although I do not expect incoming students to have any math preparation beyond calculus, students in my lab are expected to combine field work with at least some application of mathematical modeling.

Ecology and Evolution of Host-Pathogen Interactions.

The main area of my research focuses on interactions between insects and their associated pathogens. Many forest insects experience dramatic population fluctuations, in which their density varies over 4-5 orders of magnitude. The peaks of these outbreaks are often terminated by epidemics of nuclear polyhedrosis viruses that cause individual insects to liquefy, and that can wipe out entire insect populations. My work has shown that measurements of disease transmission rates from field experiments can be used in simple epidemic models to predict the timing and intensity of these epidemics. A key component of these models, however, is variability in resistance in the insect population. My current research in this area is therefore aimed at understanding whether this variability has a genetic basis, and thus at quantifying the extent to which the evolution of disease resistance plays a role in insect outbreaks.

More recently, my work with host-pathogen interactions has branched out to consider plant pathogens, in collaboration with Joy Bergelson (also a member of Ecology and Evolution at U. Chicago). We are exploring the extent to which the ecology of the interaction between the host plant and its pathogens is reflected in patterns of variability in DNA sequence data. This work suggests that disease models can play an important role in understanding the evolutionary history of disease resistance genes.

Spatial Ecology

Ecological theory has classically ignored the effects of the spatial distribution of animals and plants on species interactions. An important area of my research is aimed at extending this theory to include space, and to use it to understand field data. The two most current active questions that I am addressing are, first, how does the behavior of insect larvae affect their risk of infection? My field data suggest that the behavior of these insects changes after an epidemic, apparently because the disease is transmitted during feeding. In collaboration with my student Kevin Drury, I am developing models to understand how feeding behavior affects the risk of infection, and thus epidemic intensity. Second, in collaboration with Bill Morris at Duke University, I am working on a theory to understand how plant quality interacts with insect movement behavior to determine the spatial dynamics of insect populations.

Ecology of Invasions and Conservation Biology

My most recent work, in collaboration with David Lodge at Notre Dame and my student Kevin Drury, is a project aimed at predicting whether potentially-invasive aquatic species will invade the Great Lakes. This project requires the parametrization and analysis of stochastic population growth models, much like those used in conservation biology. The close parallel to conservation biology has led to an additional project on the conservation of rare Midwestern butterflies with my partner Alison Hunter, who teaches biology at U. Chicago.

Recent Publications

G. Dwyer, S.A. Levin, and L. Buttel. 1990.

A simulation model of the population dynamics and evolution of myxomatosis. Ecological Monographs. 60(4): 423-447.

G. Dwyer. 1991.

Density, stage, and patchiness in the transmission of an insect virus. Ecology. 72(4):559-574.

G. Dwyer. 1992.

On the spatial spread of insect pathogens: theory and experiment. Ecology. 73: 479-494.

G. Dwyer. and J. S. Elkinton. 1993.

Using simple models to predict virus epizootics in gypsy moth populations. Journal of Animal Ecology. 61,1-11.

G. Dwyer.

Density-dependence and spatial structure in the dynamics of insect pathogens. 1994. The American Naturalist. 143: 533-562.

G. Dwyer and J. S. Elkinton. 1995.

Host dispersal and the spatial spread of insect pathogens. Ecology. 76: 1262-1275.

W. F. Morris and G. Dwyer. 1997.

Population consequences of constitutive and inducible plant resistance: herbivore spatial spread. The American Naturalist. 149: 1071-1090.

G. Dwyer, J. S. Elkinton, and J. P. Buonaccorsi. 1997.

Host heterogeneity and the dynamics of infectious disease: tests of a mathematical model. The American Naturalist. 150: 685-707. (winner of the Mercer Award of the Ecological Society of America).

A. Hunter and G. Dwyer. 1998.

Outbreaks and interacting factors: insect population explosions synthesized and dissected. Integrative Biology. 1:166-177.

G. Dwyer, A. E. Hajek, and J.S. Elkinton. 1998.

Spatial scale and the spread of a fungal pathogen of gypsy moth. The American Naturalist. 152:485-494.

Stahl E. A., G. Dwyer, R. Mauricio, M. Kreitman and J. Bergelson. 1999.

Dynamics of disease resistance polymorphism at the Rpm1 locus of Arabidopsis. Nature. 400:667-671.

Dwyer, G., J. Dushoff, J.S. Elkinton and S.A. Levin. 2000.

Pathogen-driven outbreaks in forest defoliators revisited: building models from experimental data. The American Naturalist. The American Naturalist. 156: 105-120.

G. Dwyer, J. Dushoff, J.S. Elkinton, J.P. Burand, S.A. Levin. 2000.

Host heterogeneity in susceptibility: lessons from an insect virus. To appear in Virulence Management U. Diekmann, K. Sigmund, M. Sabelis, J.A.J. Metz, editors. Cambridge University Press.

J. Dushoff and G. Dwyer. 2000.

Evaluating the risks of engineered viruses: modelling pathogen competition. Ecological Applications, in press.