Insect ecology in agroecosystems

      I am broadly interested in community-level interactions among species and have been motivated since my first experiences in ecological research to understand the consequences of these interactions for the health and persistence of ecosystems. I am also interested in the role that human-mediated change plays in shaping the outcome of interactions between organisms and the environment. While my research experiences have allowed me to work with a variety of different organisms, I have found my niche working with insects and exploring the diverse interactions that allow this group to be both successful and essential members of all kinds of ecological communities.

1. Tracking pesticide drift and potential risks for beneficial insects.

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      I am currently a postdoctoral researcher working with Christian Krupke to examine the impacts of pesticide-treated seeds on arthropod communities, particularly beneficial insects such as pollinators.

      Along with several other crops, corn and soybean seeds are coated with pesticides prior to planting so that they might be protected early in their growth from damage by insects, pathogens, or fungi. Neonicotinoids are the main components of the seed-coating that provide protection against insects, and while they are effective insecticides, they are highly toxic to beneficial insects like honey bees and other pollinators. During planting, fragments of pesticide coating separate from the seeds, mix with seed lubricants like talc or graphite (when they are used), and eventually enter the air via the exhaust system of planting equipment. This "contaminated dust" poses a risk to surrounding areas in the environment via unintended exposure to pesticide residues.

      Our goal is to gain a better understanding of how far this contaminated dust travels across agricultural landscapes and what the potential levels of exposure might be for pollinators, like honey bees, that may be foraging for resources in vicinities where treated-seeds are planted. We further plan to expand our evaluation of the impacts of these compounds in agro-ecosystems to include the influence of different farming practices (i.e. cover-cropping) on the likelihood of pesticide exposure for both pollinators and other beneficial species of insects that provide ecosystem services, like natural pest suppression.

 

      While predator diversity effects on natural pest suppression are well-known, the implications of predator diversity for plant disease may be harder to predict given that predators indirectly influence pathogen prevalence via their direct impacts on vector abundance, distribution and/or feeding behavior. For example, if there are fewer vectors present in the presence of species-rich predator communities, or if vectors engage in predator avoidance behaviors rather than feeding on host plants, then predator diversity may contribute to reductions in the prevalence of plant pathogens. However this is just one example, and the consequences of diversity for insect-vectored plant pathogens may vary dramatically depending on the details of the pathogen system.

       My doctoral research addressed the question of whether promoting greater predator species richness influences the ability of predatory insect communities to provide effective biological control of bird cherry-oat aphids in wheat systems and furthermore, whether suppressing populations of these aphids had implications for the prevalence of the aphid-vectored Cereal yellow dwarf virus (CYDV) in wheat. Overall, I found that increasing predator diversity had no impact on the prevalence of CYDV in wheat habitats; however, the presence of a predator assemblage, regardless of species richness, did significantly reduce the proportion of plants infected. The results of my research suggest that declines in predator species richness may not have immediate consequences for vector-borne pathogen outbreak; however, promoting predator communities may have benefits for the management of insect-vectored pathogens.

       I'm really interested in community-level, multi-trophic interactions and I hope to continue to pursue an understanding of how human-mediated changes, like reductions in biodiversity and habitat simplification, shape the outcome of ecological proceses like disease dynamics and what the consequences will be for the stability and health of ecosytems in the future.

3. Impacts of habitat fragmentation on ecosystem functioning at the landscape scale.

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      Prior to graduate school, I was a research technician on the Corridor Project, a large scale habitat fragmentation experiment aimed at understanding the consequences of human-mediated changes to the landscape for various ecosystem processes such as dispersal, seed predation, and habitat restoration. During my time on this project I conducted an independent study in which I evaluated the impacts of habitat connectivity on seed dispersal by quantifying seed rain in a longleaf pine ecosystem. Perhaps one of the most interesting findings from this work was that the most significant factor contributing to both the number and species richness of seeds in traps was not connectivity among habitat patches, but rather distance from the patch edge. We found that as distance from the edge increased, there were significantly greater numbers and species of seeds found in seed traps. These results could provide valuable insight into the means by which patch size and shape may be mediating dispersal processes within fragmented landscapes.

Research activities & interests