RESEARCH

Carl Sagan suggested “it would be wryly interesting if, in human history, the cultivation of marijuana led generally to the invention of agriculture and thereby to civilization.” Sagan’s proposal may not be as far-fetched as it seems. Cannabis cultivation dates back 12,000 years, providing early civilizations with a versatile array of resources. And let's be honest, if Carl Sagan found it intriguing, it's definitely worth exploring!

Defending with diversity - Phytochemicals mediate ecological interactions

Phytochemical's mediate interactions between plants and their environment and potentially function as plant defenses, both in isolation and when acting as part of a suite of compounds. However, many isolated phytochemicals are in fact not functional as defenses or toxins when tested in biological assays, while entire assemblages of compounds (e.g., measured as phytochemical diversity) can have powerful toxic and deterrent effects. Hypotheses proposed to explain the effects of phytochemical diversity postulate that plants which possess diverse phytochemicals maintain a greater selective advantage when defending against diverse natural enemies. I am particularly interested in these plant-insect interactions and how abiotic stress, such as drought, affects phytochemistry. To investigate this potentially widespread, but understudied component of ecological interactions, I have turned to the chemically unique taxa - Cannabis sativa.

Cannabis sativa has evolved more than 480 compounds phytochemicals and is unique from other taxa due to its ability to produce an abundance of diverse cannabinoids. Its high interclass and intraclass diversity yields high functional diversity among Cannabis populations and provides multiple opportunities to investigate how variations in functional diversity affect arthropod communities. To achieve this, I have combined observational and experimental studies to characterize effects of phytochemical variation on naturally occurring insect communities associated with Cannabis. Additionally, we utilized controlled laboratory conditions to test specific hypotheses about effects of abiotic stress - specifically drought- on phytochemistry and the subsequent impact on insect communities and Lepidopteran physiology.

Bugs in the bud: An entomological road trip through Cannabis fields of the West

Since 2017, I have collected more than 4,000 arthropods from outdoor Cannabis (hemp and marijuana) fields across five western states - California, Nevada, Oregon, Colorado and Nebraska- representing 10 insect orders. This extensive observational data provides a comprehensive overview of the insect communities associated with Cannabis grown for cannabinoid production. Additionally, I conducted targeted sampling of Lepidopteran pests, including Helicoverpa zea, to establish a wild-caught colony for feeding bioassays.

Parched but productive: How drought alters hemp phytochemistry and its ripple effects on the associated insect community

Cannabis is a multipurpose plant grown for fiber, oil, seed and its purported medicinal and recreational uses, with hemp and marijuana cultivated for cannabinoid production, including CBD and THC, respectively. At the time of this work, most hemp grown in the U.S. was for CBD production which became the focus of our research. Producers aim to increase the yield of these phytochemicals while minimizing inputs. Research indicates that drought stress can increase the concentration of target phytochemicals, but whether this translates to an overall increase in the net yield of these phytochemicals remains unclear.

To explore this, we grew 150 hemp plants outdoors at the NV Agricultural Experiment Station Greenhouse Complex in 2018, 2019 and 2020, applying three different water treatments to examine how soil moisture levels effect CBD concentration, net yield, and phytochemical diversity. Additionally, we investigated how changes in phytochemistry might mediate interactions with the insect community by collecting arthropods from the plants to observe any effects on insect community and herbivory. The harvested plant matter was also used to create artificial diets for Lepidopteran feeding bioassays.

Unraveling the Impact of Hemp Phytochemicals on Spodoptera Growth and Survival with Feeding Bioassays

We conducted laboratory-based feeding experiments using performance bioassays on Spodoptera using mixtures that range above and below naturally occurring concentrations and proportions observed in hemp plants grown at the UNR Greenhouse Complex. These bioassay were prepared using coarse extracts from the hemp cultivated in our drought experiment. Our focus is on examining the effects on growth rates, development time, survivorship, and fecundity. We plan to use Helicoverpa zea in future feeding bioassays.

Into the wild: The effects of natural and artificial selection on hemp phytochemistry and arthropod communities

Agricultural domestication has shaped human civilization and ecosystem processes, often leading to reduced genetic and phytochemical diversity in cultivated plants. This research compares cultivated and feral hemp to explore differences in phytochemical profiles and their impact on their associated arthropod communities. Focusing on how natural and artificial selection influence these dynamics, the study sheds light on the ecological effects of domestication. Conducted in Nebraska in 2020, where both feral and cultivated hemp populations coexist, this work has important implications for agricultural practices, biodiversity conservation, and the sustainable management of hemp crops.

Research Assistantships

Research Assistant, The Gompert Lab
Utah State University
July-December 2022
Quantified cuticular hydrocarbons (Lepidoptera) using GC-FID.

Research Assistant, Cooperative Extension
University of Nevada, Reno
February-October 2022
Assisted with outreach including Hemp Field Days, wrote and published Extension Fact Sheets, and lead undergraduate workers in final field experiment data collection and harvest.