Articles by Eric S. Michel in JoVE
Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid Eric S. Michel1,2, Emily B. Flinn1, Stephen Demarais1, Bronson K. Strickland1, Guiming Wang1, Chad M. Dacus3 1Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, 2Department of Natural Resource Management, South Dakota State University, 3Mississippi Department of Wildlife, Fisheries and Parks Phenotypic differences among cervid populations may be related to population-level genetics or nutrition; discerning which is difficult in the wild. This protocol describes how we designed a controlled study where nutritional variation was eliminated. We found that phenotypic variation of male white-tailed deer was more limited by nutrition than genetics.
Other articles by Eric S. Michel on PubMed
Contrasting the Effects of Maternal and Behavioral Characteristics on Fawn Birth Mass in White-Tailed Deer PloS One. 2015 | Pubmed ID: 26288141 Maternal care influences offspring quality and can improve a mother's inclusive fitness. However, improved fitness may only occur when offspring quality (i.e., offspring birth mass) persists throughout life and enhances survival and/or reproductive success. Although maternal body mass, age, and social rank have been shown to influence offspring birth mass, the inter-dependence among these variables makes identifying causation problematic. We established that fawn birth mass was related to adult body mass for captive male and female white-tailed deer (Odocoileus virginianus), thus maternal care should improve offspring fitness. We then used path analysis to identify which maternal characteristic(s) most influenced fawn birth mass of captive female white-tailed deer. Maternal age, body mass and social rank had varying effects on fawn birth mass. Maternal body mass displayed the strongest direct effect on fawn birth mass, followed by maternal age and social rank. Maternal body mass had a greater effect on social rank than age. The direct path between social rank and fawn birth mass may indicate dominance as an underlying mechanism. Our results suggest that heavier mothers could use dominance to improve access to resources, resulting in increased fitness through production of heavier offspring.
EAR AND TAIL LESIONS ON CAPTIVE WHITE-TAILED DEER FAWNS (ODOCOILEUS VIRGINIANUS): A CASE STUDY Journal of Zoo and Wildlife Medicine : Official Publication of the American Association of Zoo Veterinarians. Jun, 2016 | Pubmed ID: 27468041 During the 2008-2011 time period, undiagnosed lesions were observed in 21 of 150 white-tailed deer fawns (Odocoileus virginianus) that were part of a captive deer herd at Mississippi State University. Clinical findings in healthy and diseased fawns from 0 to 90 days of age included bite and scratch marks followed by moderate to severe ear and tail necrosis. Gross necropsy findings of necrotizing ulcerative dermatitis correlated with histopathologic findings that included focally severe multifocal vasculitis, vascular necrosis, and thrombosis. This article is a clinical description of these previously unreported lesions associated with tissue necrosis in young captive white-tailed deer.
Improved Nutrition Cues Switch from Efficiency to Luxury Phenotypes for a Long-lived Ungulate Ecology and Evolution. Oct, 2016 | Pubmed ID: 27942376 Cervid phenotype can be categorized as efficiency, which promotes survival but not extravagant growth, or luxury which promotes growth of large weaponry and body size. Although nutritional variation greatly influences these phenotypic forms, the potential for subspecies-linked genetic or founder effects from restocking efforts of harvested species has not been eliminated. We measured intergenerational phenotypic change of males in response to improved nutrition in three captive-reared populations of white-tailed deer. Study animals were offspring of females captured from three regions displaying variation in antler and body size as well as nutritional variation. We fed all animals a high-quality diet and measured antler and body size for two generations. We predicted that improved long-term nutrition would cue a switch from efficiency to luxury phenotype for all populations and that regional compensation of antler and body size would occur. Improved nutrition positively influenced all measures of antler and body size; however, changes varied in magnitude. Antler size was more responsive than body size. Improved nutrition also facilitated regional compensation of antler size and partial compensation of body size. Our results show that improved long-term nutrition cues a shift from efficiency to luxury phenotype in a long-lived cervid with weaponry being more responsive than body size. Compensation of antler size suggests that weaponry is greatly influenced by nutrition and is not restricted by subspecies-linked genetic or founder effects from restocking efforts related to our regional populations. Therefore, strategies to improve cervid antler and body size should include habitat management that elevates long-term diet quality.