Semester of Graduation
Fall 2025
Degree
Master of Science (MS)
Department
Department of Entomology
Document Type
Thesis
Abstract
Emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive pest that threatens ash trees (Fraxinus spp.) throughout North America and Europe. Since its introduction to North America, EAB has killed hundreds of millions of trees, resulting in severe ecological and economic damage exceeding 10 billion US dollars. Classical biological control involves the introduction of natural enemies from the native range of pests to manage their populations. Specialist parasitoid wasps have been released to reduce the populations of EAB. Detection and response to long-range attractants associated with EAB is critical for the location and parasitism by classical biological control agents. The ash foliage has been shown to be an important cue for the two species of Spathius wasps. The physiological state of parasitoids may vary across environmental conditions and has been predicted to alter host-location behaviors and biological control success. However, the impact of physiological differences on parasitoids’ ability to detect and respond to host-associated cues is crucial to understanding their foraging behavior. I evaluated how adult feeding influences the survival and number of mature eggs of two species of Spathius wasps to optimize parasitoid release strategies. The response of wasps to attractants was tested in a four-arm olfactometer under varying physiological conditions. Wasps were fed or starved before bioassays. I validated the response of Spathius agrili Yang to a known attractant (green ash foliage) in a behavioral arena that had not been previously used with this species (a four-arm olfactometer). Additionally, I demonstrated that Spathius galinae Belokobylskij is also attracted to the foliage of green ash. Both species of Spathius can detect and respond to foliage from young and old green ash trees. I described the reproductive systems of S. agrili and S. galinae morphologically for the first time using fluorescent microscopy. Nutritional stress shifts their preference toward younger trees, reduces survivorship, and decreases the number of mature eggs available for oviposition. These studies contribute to classical biological control by connecting natural enemy physiology to establishment and parasitism rates across environmental gradients, making predictions about differences in the success of biological control of EAB in southeastern ecosystems, with an emphasis on subtropical Louisiana.
Date
11-3-2025
Recommended Citation
Jindal, Vanshika, "Impact of physiological and environmental variation on the behavioral response of the two biological control agents of the emerald ash borer to host-associated odors" (2025). LSU Master's Theses. 6225.
https://repository.lsu.edu/gradschool_theses/6225
Committee Chair
Johnson, Todd D.
Student Approval Forms
Included in
Behavior and Ethology Commons, Entomology Commons, Environmental Studies Commons, Forest Sciences Commons, Integrative Biology Commons