Date of Graduation


Document Type


Degree Type



Davis College of Agriculture, Natural Resources and Design


Division of Plant and Soil Sciences

Committee Chair

Teiya Kijimoto

Committee Member

Kimberly Barnes

Committee Member

Daniel Panaccione


An organism’s phenotype can be affected in development by alterations to gene expression based on environmental inputs. Nutrition is one such environmental input and the central regulator of development of large horn or small horn phenotypes in the dung beetle species, Onthophagus taurus. However, little is known about the nature of chemical compounds that are critical to this plastic horn development. To better understand these compounds, we are utilizing an untargeted metabolomic approach as well as a targeted gene approach. Through the metabolomic approach, it was uncovered that environmental conditions tend to have a greater impact on metabolomic composition than sex. In addition, several discovered metabolites were indicative of different environmental conditions. Under our genetic approach, we discovered that a phosphatidylinositol-4-phosphate (PI4Kiiia) knockdown results in animals having a greater mean horn size, more variance in horn width, and many horn shapes not seen in control animals.