RESEARCH INTERESTS

My small research group emphasizes tritrophic (plant-herbivore-natural enemy) interactions as influenced by abiotic factors (edaphic and weather). Our physiologically based mathematical and computer simulation models have a common mathematical root and form across all trophic levels and are based detailed field and laboratory data. Our models integrate the biology of consumer behavior and physiology that affects resource acquisition and allocation and hence population birth and death rates. Bottom-up effects of resources availability (i.e., the interplay between the rate of per-capita resource acquisition (the supply) and the per capita genetic demand rate) define the underlying base dynamics of each species. Natural enemies provide the top-down or regulatory effects and refine the details of the observed dynamics. Analogies between the economy of nature and humans has allowed the extension of our tritrophic model to examine the economic theory of renewable resource management.

Our models have been used to analyze diverse agro- and other ecosystems world wide, to assess the theory and practice of biological control, to solve practical problems in crop production and pest management (CP/IPM), and to explore economic and theoretical issues. Among the multitrophic systems models developed are those for alfalfa, apple, cassava, coffee, common bean, cotton, grape, rice and agroforestry. This research relies heavily on interdisciplinary cooperative efforts with research groups worldwide. Analysis of the theoretical bases of our supply/demand model has received considerable recent attention.

CURRENT PROJECTS

Our research focuses on four interrelated areas: (1) Refinement of existing models and the completion of models for coffee/coffee berry borer/three parasitoids in Central, South America and Mexico and migratory desert locust in North Africa. The development of the coffee systems model is a collaborative project with Brazilian and Colombian colleagues. The work on locust is part of a large international humanitarian effort by ICIPE/UNDP/FAO to assess the outbreak potential of this important migratory pest. The work on locust seeks to develop methods for predicting the outbreak potential of locust in North Africa and the Middle-East -- an area twice as large as the continental United State. To accomplish this task, a GIS system will be used to integrate satellite remote sensing data, edaphic factors and dynamics models of locust - host plant(s) biology. (2) Develop a metapopulation (object oriented) model of the cassava tritrophic systems. Our object oriented models treat plants as individuals (patches) each having populations of herbivores and natural enemies that migrate between plants based on local supply-demand considerations. Each plant may be a different species or variety, age, have different spatial coordinates, and may grow on different soil types and variable nutritional and water status. The model may be run deterministically or stochastically. The same modeling framework is used to model sub regions of larger geographic areas in GIS regional analyses. (3) Geographical information system (GIS) for mosquitoes and four major crops in California (i.e., alfalfa, cotton, grape and rice). A GIS system enables one to map a geographic region with respects to several variables (elevation, rainfall, soil type, biological variables, etc.), to create synthetic ones by combining variables, to include models to simulate crop-pest-natural enemy development at specific sites or regionally using satellite or other sources of weather data to drive the models, etc.. Our GIS system is designed to analyze plant-herbivore-natural enemy interactions on a regional scale in California, but it is general enough to be applied to any area.

(4) Theoretical studies on food web dynamics. Considerable progress has been made in analyzing the underlying theory of our models, and in extending the models to the analyses of the ecology and economics of food webs. The objective is to bridge the gap between purely theoretical models and models that have measurable parameters.

SELECTED PUBLICATIONS

Gutierrez, A. P. 1970. Studies on host selection and host specificity of the aphid hyperparasite Charips victrix (Hymenoptera: Cynipidae). VI. A synopsis of host selection and a description of the sensory structures. Annals Ent. Soc. Amer. 63: 1705-1709.

Gutierrez, A. P., D. E. Havenstein, H. A. Nix and P. A. Moore. 1974. The ecology of Aphis craccivora Koch and subterranean clover stunt virus. III. A regional perspective of the phenology and migration of the cowpea aphid. J. Appl. Ecol. 11: 21-35.

Regev, U., A. P. Gutierrez and G. Feder. 1976. Pests as a common property resource: a case study in the control of the alfalfa weevil. J. Agric. Econ. 58: 186-97.

Wang, Y., A. P. Gutierrez, G. Oster and R. Daxl. 1977. General population model for plant growth and development: coupling cotton-herbivore interactions. Can. Entomol. 109: 1359-1374.

Wermelinger, B., J. Baumgartner and A. P. Gutierrez. 1991. A demographic model of assimilation and allocation of carbon and nitrogen in grapevines. Ecol. Modelling 53: 1-26.

Gutierrez, A. P., J. S. Yaninek, B. Wermelinger, H. R. Herren and C. K. Ellis. 1988 Analysis of biological control of cassava pests in Africa: III. Cassava green mite Mononychellus tanajoa. J. Appl. Ecol. 25: 941-950.

Gutierrez, A. P., W. J. Dos Santos, M. A. Pizzamiglio, A. M. Villacorta, C. K. Ellis, C.A.P. Fernandes and I. Tutida. Modelling the interaction of cotton and the cotton boll weevil. II. Boll weevil (Anthonomus grandis) in Brazil. J. Appl. Ecol. 28: 398-418.

Gutierrez, A.P. 1992. The physiological basis of ratio dependent theory. Ecology 73:1529-53.

Gutierrez, A.P., J.R. Hakim Cure E. Mariot and A. Villacorta. 1993. A model for the growth and development of three varieties of common bean (Phaseolus vulgaris L.): Factors affecting yield and quality. Agricultural Systems 44: 35-63.

Gutierrez, A.P., P. Neuenschwander,and J.J.M. van Alphen 1993. Factors affecting biological control of the cassava mealybug exotic parasitoids: a ratio-dependent supply-demand driven model. J. Appl. Ecol. 30:706-721.

Gutierrez, A.P., S.J. Mills, S.J. Schreiber and C.K. Ellis 1994. A Physiologically Based Tritrophic Perspective on Bottom-Up-Top-Down Regulation of Populations. Ecology 75: 2227-2242.

Berryman, A.A., J. Michalski, A.P. Gutierrez and R. Arditi 1995. Logistic theory of food web dynamics. Ecology 76: 336-343.

Gutierrez, A.P. 1996. 1996. Applied Population Ecology: a supply-demand approach. John Wiley and Sons, New York. 300 pp.

Mills, N. J. and A.P. Gutierrez.. 1996. Prospective modeling in biological control: an analysis of the dynamics of heteronomous hyperparasitism. J. Animal Ecol. 33:1379-1394.

Schreiber, S.J. and A.P. Gutierrez. A supply-demand perspective of persistence in food webs: applications to biological control. Ecol. Modeling (in press)

Huffaker, C.B. and A.P. Gutierrez (editors) Ecological Entomology (2nd edition) John Wiley and Sons. (in progress)

Related links:

College of Natural Resources

Environmental Science, Policy & Management

Division of Ecosystem Science

Center of Biological Control

Center for Sustainable Development

Sebastian Schreiber