Judith Bronstein

Judith Bronstein

Professor, Ecology and Evolutionary Biology
Professor, Entomology / Insect Science - GIDP
University Distinguished Professor
Professor, BIO5 Institute
Member of the General Faculty
Member of the Graduate Faculty
Primary Department
Contact
(520) 621-3534

Research Interest

Judith L. Bronstein is University Distinguished Professor of Ecology and Evolutionary Biology, with a joint appointment in the Department of Entomology. Dr. Bronstein’s large, active lab focuses on the ecology and evolution of interspecific interactions, particularly on the poorly-understood, mutually beneficial ones (mutualisms). Using a combination of field observations, experiments, and theory, they are examining how population processes, abiotic conditions, and the community context determine net effects of interactions for the fitness of each participant species. Specific conceptual areas of interest include: (i) conflicts of interest between mutualists and their consequences for the maintenance of beneficial outcomes; (ii) the causes and consequences of "cheating" within mutualism; (iii) context-dependent outcomes in both mutualisms and antagonisms; and (iv) anthropogenic threats to mutualisms. In addition, she is Editor-in-Chief of The American Naturalist, a leading international journal in ecology and evolution. An award-winning instructor, Dr. Bronstein teaches at both the undergraduate and graduate levels; she has also run a large training grant administered by BIO5 that places life sciences graduate students in public school classrooms around Tucson. She serves in leadership positions in the College of Science (including chairing the College of Science Promotion and Tenure Committee for 2013), at the University, and at the Arizona-Sonora Desert Museum, where she is a member of the Board of Trustees and Chair of the Science and Conservation Council.

Publications

Bronstein, J. L., Wilson, W. G., & Morris, W. F. (2003). Ecological Dynamics of Mutualist/Antagonist Communities. American Naturalist, 162(4 SUPPL.), S24-S39.

PMID: 14583855;Abstract:

One approach to understanding how mutualisms function in community settings is to model well-studied pairwise interactions in the presence of the few species with which they interact most strongly. In nature, such species are often specialized antagonists of one or both mutualists. Hence, these models can also shed light on the problem of when and how mutualisms are able to persist in the face of exploitation. We used spatial stochastic simulations to model the ecological dynamics of obligate, species-specific mutualisms between plants and pollinating seed parasite insects (e.g., yuccas and yucca moths) in the presence of one of two obligate antagonist species: flower-feeding insects (florivores) or insects that parasitize seeds but fail to pollinate (exploiters). Our results suggest that mutualisms can persist surprisingly well in the presence of highly specialized antagonists but that they exhibit distinctly different temporal and spatial dynamics when antagonists are present. In our models, antagonists tend to induce oscillations in the mutualist populations. As the number of per capita visits by antagonists increase, the system's oscillatory dynamics become more extreme, finally leading to the extinction of one or more of the three species. When the antagonists exhibit high per capita visitation frequencies and long dispersal distances, significant spatial patchiness emerges within these tripartite interactions. We found surprisingly little difference between the ecological effects of florivores and exploiters, although in general florivores tended to drive themselves (and sometimes the mutualists) to extinction at parameter values at which the exploiters were able to persist. These theoretical results suggest several testable hypotheses regarding the ecological and evolutionary persistence of mutualisms. More broadly, they point to the critical importance of studying the dynamics of pairwise interactions in community contexts.

Kevin, F., Joshua, N., Bronstein, J., & William, M. (2015). The demographic consequences of mutualism: ants increase host plant fruit production but not population growth. Oecologia, 435-446.