My research interests center on the ecology and evolution of plant-herbivore-natural enemy interactions. This stems from both an applied interest in the biological control of plant pests by natural enemies and a theoretical interest in the behavior, population dynamics and persistence of species comprising ecological communities. In my research program, I advocate a spatial approach to understanding these trophic interactions.
My current research interests focus on four broad areas.
1. Biogeography of plant invasions. I am particularly interested in the factors that influence invasion success over broad-geographic and temporal spatial scales. My research focuses on the invasive grass, Phragmites australis. We have explored the effects of latitude, natural enemies (i.e., herbivores, pathogens), higher trophic levels, soil microorganisms, plant genetics (ploidy, genome size, and genotypic variation), plant defensive chemistry, and climate change on invasion success and interactions with other members of the recipient community. More details about this research can be found by clicking here.
2. Causes for predator-prey population cycles. Understanding the mechanisms promoting stability of predator-prey interactions has been a longstanding interest of mine. I have been studying a model system involving the cowpea weevil (Callosobruchus maculatus) and its parasitoid (Anisopteromalus calandrae) that is known to exhibit outbreak cycles in the laboratory. My colleagues and I have been performing experiments to test the underlying causes of these outbreak cycles. Specifically, we are interested in whether changes in the age structure of the prey (specifically, the duration and variability of prey development time) affect predator-prey population cycles and stability (for more details, click here).
3. Density-dependent dispersal and predator-prey population dynamics. Dispersal can have major consequences for individual fitness, population dynamics, and species’ distributions. Understanding the causes and consequences of dispersal at both the patch and landscape levels is vital for population management and conservation. The paradigmatic view of dispersal is that it becomes more frequent as density increases. However, the pattern of density-dependent dispersal can take many forms. My colleagues and I are using mathematical models and experiments to assess how different forms of dispersal can affect population dynamics and stability. For more details about this research, click here.
4. Role of habitat fragmentation and landscape heterogeneity on predator-prey spatial and temporal population dynamics. My primary study system includes the planthopper Prokelisia crocea and its egg parasitoid Anagrus columbi that coexist among discrete patches of prairie cordgrass in the tallgrass prairies of North Dakota. My students and I have experimentally examined how cordgrass patch and landscape structure influenced host and parasitoid foraging and dispersal behavior, extinction risk, and population dynamics. My colleagues and I have also developed behavior-based landscape-level models to understand the effects of habitat heterogeneity on the population dynamics of interacting species. Offshoots of this work involved the effects of invasive exotic plants on the population dynamics of native fauna, and the use of stepping stones and corridors in promoting connectivity among habitat fragments. More details on this research project can be found by clicking here.
I welcome inquiries from prospective graduate students interested in research opportunities in my laboratory. Possible areas of study include all aspects of plant-insect interactions, insect predator-prey interactions, spatial and landscape ecology, invasion biology, and conservation biology.
For a complete list and reprints, click here
Cronin, J. T., E. Kiviat, L. A. Meyerson, G. P. Bhattarai and W. J. Allen. 2016. Biological control of invasive Phragmites australis will be detrimental to native P. australis. Biological Invasions 18(9): 2749-2752.
Meyerson, L. A., J. T. Cronin, G. P. Bhattarai, H. Brix, C. Lambertini, M. Lučanová, S. Rinehart, J. Suda and P. Pyšek. 2016. Do ploidy level and nuclear genome size and latitude of origin modify the expression of Phragmites australis traits and interactions with herbivores? Biological Invasions 18(9): 2531-2549.
Meyerson, L. A., J. T. Cronin and P. Pyšek. 2016. Phragmites as a model organism for plant invasions. Biological Invasions 18(9): 2421-2431.
Cronin, J. T., J. D. Reeve, D. Xu, M. Xiao and H. N. Stevens. 2016. Variable prey development time suppresses predator-prey cycles and enhances stability. Ecology Letters 19: 318-327.
Allen, W. J., R. Young*, G. P. Bhattarai, J. Croy*, L. A. Meyerson, A. Lambert and J. T. Cronin. 2015. Multitrophic enemy escape of invasive Phragmites australis and its introduced herbivores in North America. Biological Invasions 17: 3419-3432.
Cronin, J. T., L. A. Meyerson, G. Bhattarai and W. Allen. 2015. Biogeography of a plant invasion: plant-herbivore interactions. Ecology 96: 1115-1127.
Bhattarai, G. and J. T. Cronin. 2014. Hurricane activity and the large-scale pattern of spread of an invasive wetland plant. PLoS One 9(5): e98478. DOI: 10.1371/journal/pone.0098478.
Bezemer, T. M, J. A. Harvey, and J. T. Cronin. 2014. The response of native insect communities to invasive plants. Annual Review of Entomology 59: 119-141.
Jackson, H. B., A. Zeccarias and J. T. Cronin. 2013. Mechanisms driving the density-area relationship in a saproxylic beetle. Oecologia 173: 1237-1247.
Hakes, A. S. and J. T. Cronin. 2012. Successional change in plant resistance and tolerance to herbivory. Ecology 93: 1059-1070.