Graduate Studies

 

First Advisor

Julie A. Peterson

Second Advisor

John Ruberson

Degree Name

Doctor of Philosophy (Ph.D.)

Committee Members

Jennifer White, John DeLong, Louise Lynch-O'Brien

Department

Entomology

Date of this Version

5-2025

Document Type

Dissertation

Citation

A dissertation presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Doctor of Philosophy

Major: Entomology

Under the supervision of Professors Julie A. Peterson and John Ruberson

Lincoln, Nebraska, May 2025

Comments

Copyright 2025, Hannah E. Stowe. Used by permission

Abstract

Ecosystem services in agriculturally dominated regions rely, at least in part, on arthropods. Environment and biodiversity influence beneficial arthropods in population size, community structure, diversity, and ecosystem service provisioning. Predation is among the most important services provided by arthropods in agroecosystems. Understanding what alters predation and predator activity can support the successful application of biological control and, more broadly, integrated pest management. Land use and edge adjacency, field characteristics, landscape, seasonality, and diel period all alter predatory behavior. Crop fields dominate Nebraska agroecosystems, although interspersed perennial grasslands persist through the Conservation Reserve Program (CRP). Such grasslands supply crucial resources and habitat for wildlife important to High Plains ecology. We investigated arthropod activity density; family diversity; and sentinel prey consumption amount, frequency, timing, and predator identity in crop fields and adjacent grasslands. We collected above ground and epigeal arthropods monthly from May to September, 2022–2023 with sticky cards and pitfall traps; measured and recorded consumption of moth egg and fly pupae sentinel prey using time lapse cameras. Further we conducted qualitative interviews with landowners of either CRP or crop fields. Land use and edge adjacency influenced predator activity density and family richness differently between epigeal and above ground guilds, although both were affected by landscape factors. Sentinel prey consumption varied across months, land use, and edge adjacency. Prey visitation was highest in grass centers, although aerial visitor richness decreased as the season progressed. Structural equation modeling indicated that landscape factors were important determinants of prey visitors and consumption. In both communities, prey consumption was not directly related to predator activity density, and only slightly influenced by aerial predator richness. Nebraska landowners perceive wildlife and ecology as an interconnected system of essential parts, linked by personal experiences, and understand principles governing organism interactions, food webs, and ecosystem services. Understanding the ecology that influences predators and predation can reveal which arthropods contribute major predation services and suggest how to ensure that these organisms continue to thrive in the landscape.

Advisors: Julie A. Peterson and John Ruberson

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