Browsing by Author "Hopkins, Brittney Cole"

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    Like mother, like offspring: maternal and offspring wound healing correlate in snakes
    Hopkins, Brittney Cole; Chin, Stephanie Y.; Willson, John D.; Hopkins, William A. (Company of Biologists Ltd., 2013-07)
    Immune function early in life can be influenced by parental effects and the environment, but it remains unclear how these two factors may interact to influence immunocompetence. We evaluated maternal and environmental contributions to offspring healing ability in a viviparous reptile, the northern watersnake (Nerodia sipedon). We measured wound healing rates, a highly integrative and biologically relevant measure of innate immunity, of females and their offspring collected from sites contaminated with a toxic heavy metal and compared them with those of individuals from reference sites. We found that female watersnakes that healed the fastest produced offspring that also exhibited faster healing rates. However, we detected no influence of environmental pollution on maternal or offspring healing rates. To our knowledge, our study is the first to correlate maternal and offspring wound healing ability in a wild vertebrate.
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    Mercury Bioaccumulation and Adverse Reproductive Effects in Snapping Turtles Inhabiting a Historically Contaminated River
    Hopkins, Brittney Cole (Virginia Tech, 2012-04-10)
    Mercury (Hg) is a global pollutant that has received much attention due to its ability to bioaccumulate, biomagnify, and maternally transfers in humans and wildlife. In vertebrates, exposure to Hg can impair growth, alter behavior and morphology, decrease survival, and reduce reproductive success. Unfortunately, most ecotoxicology studies euthanize animals to quantify the concentrations of Hg bioaccumulation and in doing so eliminate the ability to relate Hg accumulation to observed effects. The development of non-destructive sampling techniques is a critical step for sustainable monitoring of Hg bioaccumulation and associated effects because it eliminates adult harvest, enables repeated sampling of the same individual over time, and allows the collection of larger sample sizes. My research aimed to develop and validate non-destructive sampling techniques for assessing Hg bioaccumulation, maternal transfer, and consumption risks in a long-lived aquatic omnivore, the common snapping turtle (Chelydra serpentina). I collected blood, nail, muscle, and egg tissues from turtles inhabiting an Hg contaminated gradient at a historically contaminated river, the South River, located in central Virginia. In my first chapter, I developed mathematical models describing relationships between the four tissues sampled and in doing so, described important demographic, spatial, and temporal factors that influence Hg bioaccumulation in turtles that may be important for ecological risk assessment and consumption. Additionally, I found that my mathematical models were applicable to other Hg contaminated locations in Virginia. In my second chapter, I examined the effects Hg bioaccumulation and maternal transfer has on turtle reproduction. I collected and incubated eggs from gravid females from reference and contaminated sites and quantified embryonic morality, infertility, and hatching success of each clutch, and assessed all hatchlings and dead embryos for gross morphological malformations. I found that Hg exposure negatively influenced hatching success through increased egg infertility and embryonic mortality. Taken together, my results are applicable to a wide array of systems where biomonitoring and assessing the ecological and consumption risk of contamination in turtles needs to be accomplished in a sustainable and conservation-minded fashion.
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    Prevalence of Ingested Fish Hooks in Freshwater Turtles from Five Rivers in the Southeastern United States
    Steen, David A.; Hopkins, Brittney Cole; Van Dyke, James U.; Hopkins, William A. (PLoS, 2014-03-12)
    Freshwater turtles may ingest baited fish hooks because many are opportunistic scavengers. Although the ingestion of fish hooks is known to be a source of mortality in multiple vertebrate groups, the prevalence of hook ingestion by freshwater turtles has not been well studied. We trapped turtles from five rivers in the southeastern United States and used radiographs to examine over 600 individuals of four species. Depending on the species, sex, and age class, 0–33% of turtles contained ingested fish hooks. For some species, larger turtles were more likely to contain a fish hook than smaller individuals. Freshwater turtle demography suggests that even small increases in adult mortality may lead to population declines. If our study areas are representative of other aquatic systems that receive fishing pressure, this work likely identifies a potential conflict between a widespread, common recreational activity (i.e., fishing) and an imperiled taxonomic group.