Determining the Diet and Contaminants Exposure of Local Field Mice Species Occupying Urban, Peri-Urban, and Rural Environments

Abstract

The focus of this research was studying field mice that inhabit a diverse array of environments, including urban, peri-urban, and rural areas. Current results suggest that the mice exhibited a varied diet presupposingly consisting of locally sourced items, including seeds, fruits, roots, and shoots from plants, with occasional consumption of small bugs and insects. Further, our analyses suggest that the field mice collected various organic materials on their hair, the significance of which needs additional study. 

Stable isotopes present in the hair samples of the captured mice were examined during the study. The mice underwent a non-invasive capture and release process. Hair samples were subjected to analysis using an isotopic ratio mass spectrometer, a sophisticated instrument providing insights into carbon isotope ¹³C and nitrogen isotope ¹⁵N. These isotopes served as indicators of the dietary history of the organisms. Elevated ¹⁵N levels suggested a diet with a higher protein content, while higher ¹³C levels indicated a preference for a plant-based protein diet.

Additionally, Gas Chromatography Mass Spectrometry (GCMS) was used to analyze the same hair samples, specifically targeting the identification of pesticides that the mice might have encountered. The local species of field mice residing in open grassland areas were the subject of investigation despite the assumed overlap in lifestyle and trophic level occupation among wild populations of these mice. 

Hair samples from the wild-caught target species were examined to compare ¹⁵N and ¹³C levels. Simultaneously, efforts were made to determine any pesticide exposure among subjects inhabiting historically disturbed habitats. The research objectives revolved around establishing the trophic level of field mice based on their dietary patterns using stable isotope analysis and determining pesticide exposure in local field mice through GCMS analysis.