CAREER: The effects of plant defenses on species interactions across biological scales

Understanding how plants interact with microbes and insects is critical for conserving ecosystems and promoting sustainable agriculture. These interactions form complex networks that shape the stability of ecological communities and support valuable ecosystem services, such as biological pest control. This research investigates how plant chemistry and leaf-associated microbes influence the behavior and population dynamics of herbivores and their predators in both natural and agricultural settings. The results will inform strategies to reduce herbivore damage, protect biodiversity, and strengthen biological control, an ecosystem service valued at $14 billion annually in the U.S. These findings can inform efforts to enhance ecosystem resilience and sustainability across both natural and agricultural landscapes. Additionally, this project will provide students with opportunities to develop critical scientific skills, gain hands-on experience, and explore careers in ecological research and applied science, supporting the scientific training of a workforce equipped to address pressing societal challenges. Plant–arthropod systems comprise over 90% of Earth’s macroscopic biomass, highlighting the critical need to understand how plant defenses shape ecological communities. As major drivers of herbivore population dynamics, plant defenses also play a pivotal role in regulating the strength of interactions between herbivores and their natural enemies. However, their broader effects on multi-level ecological interactions remain underexplored. Additionally, plant-associated microbial communities and their metabolic products (microbiomes) can significantly impact plant-arthropod interactions and community dynamics. This research employs a cross-disciplinary approach to determine the interactive effects of plant chemistry and microbiome on biodiversity, food web structure, and ecosystem stability. Specifically, it will (i) investigate how plant defenses and microbial communities influence trophic cascades and the structure of plant-microbe-arthropod networks, ii) characterize how plant defenses shape microbiome assembly, and (ii) experimentally dissect the contributions of plant chemistry and microbiota to carnivorous arthropod preference, behavior, and performance. The project also integrates a strong educational component by providing hands-on, field-based research opportunities for high school, undergraduate, and graduate students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.