Authors: Hayley Karns, Dylan Bryant, Noah Christensen, David Kirby, Sarah Marchant, Sarah Nicholas, Emmaline Saunders, Hannan Thomas, Nathan Smith, Dan Cavan, Daniele Ghiretti
Mentors: Alessandro Zanazzi
Insitution: Utah Valley University
Arthropods play a crucial role within terrestrial ecosystems by virtue of their substantial consumption of plant matter, their status as primary prey for various organisms, their function as key recyclers of organic material and nutrients in ecosystems, and their pivotal role as primary pollinators. Ground beetles (Coleoptera: Carabidae, or “Carabids”) represent a prominent and highly diverse taxonomic assemblage among arthropods inhabiting temperate forest floors. Despite their significance in these ecosystems, little is known about their trophic structure and level. These knowledge gaps primarily arise from the limitations associated with traditional investigative methods. For instance, the observation of feeding behavior in carabids proves challenging due to their diminutive size and predominantly nocturnal foraging habits. These uncertainties hinder the attainment of an understanding of community structure and trophic interactions both within the arthropod realm and with the vertebrates in their ecosystem. As a result, this research aims to gain a greater knowledge of the trophic structure of carabids using 15N/14N and 13C/12C isotopic analysis. Ground beetles were collected using pitfall traps placed near Big Springs Park (Provo Canyon, northern Utah) in September 2023. The traps were made with two plastic cups: a smaller cup was suspended inside a bigger cup. The smaller cup was partly filled with vinegar to attract the insects whereas the bigger cup was partly filled with monoethylene glycol, a compound that has been shown to preserve the insects without affecting their isotopic composition. Insect samples were collected over a period of four weeks. The beetles were then cleaned with a 2:1 mixture chloroform and methanol, dried, ground in an agate mortar and pestle, and placed in tin capsules for the isotopic analyses. Once the results are obtained, mixing model analysis will allow us to estimate the proportions of different food items based on the stable isotope ratios of consumers and food items and on known fractionations. This knowledge will contribute to a greater understanding of trophic structures and carbon pipelines in local ecosystems of northern Utah, and to a better prediction of ground beetle response to ongoing global warming and the associated changes in forest environments.