Work Description

Date: 10 February 2023 Dataset Title: Virginia opossum stable isotope data Dataset Creator: L.L. Walsh Dataset Contact: llwalsh@umich.edu Funding: American Society of Mammalogists, Southwestern Association of Naturalists, University of Michigan Ecology & Evolutionary Biology Department, Phi Kappa Phi Research Overview: Stable isotope values of carbon (d13C) and nitrogen (d15N) from Virginia opossum (Didelphis virginiana) guard hairs were analyzed to evaluate the ecology and winter adaptations in opossums by Dr. Lisa L. Walsh as part of her Ph.D. Thesis in the Ecology and Evolutionary Biology Department. The collection of stable isotope data took place from 2017 to 2019. Guard hair was processed at the University of Michigan and analyzed by the University of New Mexico Center for Stable Isotopes (UNM-CSI, USA). Captive and wild opossums were evaluated for evidence of biannual or incomplete biannual molting, a mammalian adaptation to harsh winters. Results suggest opossums do not exhibit either winter molting strategy and that guard hairs capture the opossum�s lifetime diet (Walsh and Tucker 2021). The stable isotope values were used to test the hypothesis that a Type A generalist�s niche is positively correlated with habitat heterogeneity and to evaluate which climate variables best explained isotope values. There was a positive correlation between isotopic niche size and habitat-diversity indexes (Walsh and Tucker 2020). The d13C values from opossums in the Midwest and Northeast to test whether opossums rely on anthropogenic trash to survive extreme winters. There was no significant relationship between d13C and winter variables, but there was a significant increase in variance of Midwest opossums� d13C after the 1970 corn agricultural boom (Walsh and Tucker 2023). Methodology: This dataset was generated from the guard hairs of Virginia opossums (Didelphis virginiana) collected from museum specimens and two captive opossums. All hair samples were treated with a 2:1 ratio of chloroform � methanol to remove lipids and dried under a fume hood. For each sample, 0.5 � 1.0 mg of hair was weighed with a Mettler AE 240 balance (Toledo, OH) and placed in a tin capsule (Costech, Valencia, USA) for stable isotope analysis of d13C and d15N values conducted by UNM-CSI. For each opossum, two hair samples were analyzed, and each hair sample�s stable isotope values are listed separately in the dataset. For ecological analysis, the samples were averaged for an individual�s stable isotopic value. Please note that samples were collected across a century and are presented as the raw data in this file (no corrections for changes in atmospheric 13C have been applied to this dataset). To analyze organic substrates, UNM-CSI uses a Delta V mass spectrometer (Thermo Scientific, Waltham, USA) with a Conflo IV interface 4010 elemental analyzer (Costech, Valencia, USA). Analytical error across 56 runs of the UNM-CSI protein standard (casein) was 0.1099 standard deviations (SD) for d15N and 0.0543 SD for d13C. Instrument and/or Software specifications: NA Institution Acronyms: Angelo State Natural History Collections (ASNHC), UC Santa Barbara Cheadle Center for Biodiversity and Ecological Restoration (CCBER), Washington State University Charles R. Conner Museum (CRCM), California State University Chico Vertebrate Museum (CSUC), California State University Long Beach (CSULB), Cornell Museum of Vertebrates (CUMV), Field Museum of Natural History (FMNH), Humboldt State University Vertebrate Museum (HSU), Natural History Museum of Los Angeles County (LACM), Louisiana State University Museum of Natural Science (LSU), Harvard University Museum of Comparative Zoology (MCZ), University of New Mexico Museum of Southwestern Biology (MSB), Michigan State University Natural Science Collections (MSU), UC Berkeley Museum of Vertebrate Zoology (MVZ), University of Michigan Mammal Collection Number (MZ), New York State Museum (NYSM), Sam Noble Oklahoma Museum of Natural History (OMNH), Ohio Wildlife Center (OWC), Royal Ontario Museum (ROM), Museum of Texas Tech University (TTU), University of Alaska Museum (UAM), University of Michigan Museum of Zoology (UMMZ), National Museum of Natural History Smithsonian Institution (USNM), and University of Washington Burke Museum (UWBM). Files contained here: - Walsh_Didelphis_virginiana_Stable_Isotope_Data.csv� = the raw data d13C and d15N data for 153 museum specimens and two captive opossums. Related publications: Walsh, L.L. �and P.K. Tucker. 2020. Habitat heterogeneity is correlated with isotopic niche breadth across the range of a mammalian generalist mesopredator.� Ecosphere, 11(12): e03314. Walsh, L.L. �and P.K. Tucker.� 2021. Stable isotope values suggest opossums (Didelphis virginiana) at their northern edge do not seasonally molt. Northeastern Naturalist, 28(1): 1-8. Walsh, L.L., and P.K. Tucker. 2023. Evaluating anthropogenic influence on a mesopredator: Opossum (Didelphis virginiana) isotope values influenced by corn agriculture more than urbanization. Canadian Journal of Zoology, 101: https://doi.org/10.1139/cjz-2021-0172.� Use and Access: This data set is made available under a Creative Commons Attribution-NonCommercial license (CC BY-NC 4.0). To Cite Data: Walsh, L. L. Virginia opossum stable isotope data [Data set], University of Michigan - Deep Blue Data.