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The Food Habits Of Ictalurus Natalis, Centrarchus Macropterus And Perca Flavescens In Lake Drummond In The Dismal Swamp Of Virginia, Steven C. Russell

Biological Sciences Theses & Dissertations

The food habits of yellow bullhead catfish (Ictalurus natalis), yellow perch (Perea flavescens), and fliers (Centrarchus macropterus) in Lake Drummond in the Dismal Swamp were examined. Seventy yellow bullheads (42 mm to 255 mm), 136 yellow perch (41 mm to 280 mm), and 110 fliers (81 mm to 140 mm), were collected with gill nets, traps, seins, and electro-fishing gear from June through November of 1975. Frequency of occurrence and volumentric data were used to evaluate the relative importance of food items. Spearman's rank correlation coef­ficient was determined from the data to test differences …

An Intensive Study Of The Spring Phytoplankton Bloom In Lynnhaven Bay, Virginia, Donald Lynn Webster

Biological Sciences Theses & Dissertations

Phytoplankton samples were collected biweekly from two stations, one in each branch of Lynnhaven Bay, Virginia over the period January 24 to June 9, 1975. Water temperature, salinity, pH, oxygen, ammonia, urea, reactive nitrite, reactive nitrate, reactive phosphorus, productivity, transparency, and weather conditions were recorded concurrently. Data were manipulated employing analysis of variance, simple correlation, correlation matrices, and forward stepwise multiple regression. Total phytoplankton numbers exhibited a unimodal pattern. A pre-bloom pulse was recorded at both stations in late February. The spring bloom lasted from April through May. Phytoplankton growth was primarily a function of nutrient supply and temperature. Nutrient …

Sex Pheromone Activity In The Foveal Glands In The Two Species Of Ixodid Ticks: Dermacentor Andersoni (Stiles) And Dermacentor Variabilis (Say), Lynn Anne Collins

Biological Sciences Theses & Dissertations

Sex pheromone activity in the foveal glands of female Dermacentor andersoni (Stiles) and Dermacentor variabilis (Say) is described. Autoradiography revealed the accumulation of ³⁶Cl in the foveal glands of females during their first 120 hours of feeding on a ³⁶Cl-labeled host. Emissions collected from these females contained a ³⁶Cl-labeled product. This product, however, was absent in emissions collected from the same females with their foveae dorsales obstructed.

Accumulation of ³⁶Cl in the foveal gland, in conjunction with the release of a ³⁶Cl-labeled product through the foveae dorsales, suggest localization of sex pheromone activity within these …

Structural Comparisons Of Four Plant Communities In The Great Dismal Swamp, Claire Virginia Dabel

Biological Sciences Theses & Dissertations

Four plant communities in the Great Dismal Swamp, located on the coastal plain in southeastern Virginia, were sampled and estimates of density, basal area and aboveground standing crop biomass were determined, Biomass was estimated as 229,800 kg/ha in the Chamaecyparis thyoides community and as 344,500 kg/ha in the Taxodium distichum community. Biomass for the two hardwood communities, the

Acer-Nyssa community and mixed hardwood (Quercus-Nyssa-Acer-Liriodendron-Liquidamber) community was estimated as 195,700 kg/ha and 194,600 kg/ha respectively and did not differ significantly (P

An Investigation Of The Nucleotide Cyclic 3'5' Adenosine Monophosphate In Young Hypocotyls Of Pisum Sativum L., Gary Marsh Hilton

Biological Sciences Theses & Dissertations

Concentrations of cAMP increased with time in pea hypocotyls assayed at 24 hour intervals over a period of four days. The highest concentration was 20.1 pmoles/mg protein which occurred in 96 hour hypocotyl tips. Ninety-six hour root bodies (dissected region between tip and embryo) achieved a concentration of 8.6 pmoles/mg. Concentrations of cAMP in embryos remained constant around one pmole/mg for three days and values doubled on the fourth day.

Hypocotyls, after germination for 72 hours, were dissected and incubated for various lengths of time in water and 3xl0^-8M IAA. Tips incubated for two hours showed a tenfold …

Improved Techniques For Marking, Night-Viewing, And Aging White-Tailed Deer, Odocoileus Virginianus, Barnard Hodge Powell

Biological Sciences Theses & Dissertations

These studies were concerned with the development of methods to assist investigators of wildlife population research. Specifically they involve the description of (1) A device which enables an investigator to mark deer at medium range using specially modified darts fired by conventional tranquilizer rifles, (2) Construction of infrared viewers and light sources using surplus equipment and (3) Studies to develop a method of making permanent deer dental impressions under field conditions.

Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoretic Studies Demonstrating Cytoplasmic Protein Components Unique To The Mycelial Phase And To The Yeast Phase Of Candida Albicans, Theresa Catherine Burgess

Biological Sciences Theses & Dissertations

Blastospore and mycelial cytoplasmic extracts from four strains of Candida albicans, varying in virulence, were compared by sodium dodecyl sulfate (SDS) polyacrylamide disc gel electrophoresis Cytoplasmic extracts were made by disrupting the cultures in a Braun homogenizer followed by ultracentrifugation. The supernatant fractions were then resolved on polyacrylamide gels containing SDS. Each of the preparations yielded a distinct pattern. There were mycelial specific and blastospore specific protein bands. There were more components resolved from the blastospore phase cytoplasmic extracts than from the mycelial phase cytoplasmic extracts. There were bands common to both phases. These results demonstrate protein components unique …

Variation In The Ecology Morphology And Behavior Of The Troglobitic Amphipod Crustacean Crangonyx Antennatus Packard (Crangonchidae) From Different Habitats, Gary Wayne Dickson

Biological Sciences Theses & Dissertations

Populations of the troglobitic amphipod Crangonyx antennatus living in two distinct aquatic habitats were examined for possible variations in their ecology, morphology and behavior. Collections were made seasonally for one year in six Lee Co., Virginia caves, three containing mud-bottom, drip pools and three with small gravel stream habitats. Environmental parameters thought to influence population variation were quantitatively and qualitatively recorded in each of the six caves.

Amphipod densities, body length, female maturity, clutch number and stream washout rates were found to be greater in drip pool habitat populations. Variation was also observed in body coloration and antennal segment-body length …

The Distribution Of Submersed Hydrophytes In Currituck Sound, Steven Harry Davis

Biological Sciences Theses & Dissertations

The rooted submergent flora of Currituck Sound, North Carolina was determined, and the distributions of its species investigated with respect to salinity, substrate texture, depth, pH, turbidity and species co-occurrence. Eight species of hydrophytes were found: Potamogeton pectinatus, Fotamogeton perfoliatus, Ruppia maritima, Zannichellia palustris, Najas guadalupensis, Elodea nuttallii, Vallisneria americana, and Myriophyllum spicatum. The mean salinities at which each species occurred ranged from 1.0 ppt for E. nuttallii to 3.1 ppt for Z. palustris, Ruppia maritima, Z palustris and V. americana were the only species that commonly occurred on coarse-grained substrates. Elodea nuttallii and N. guadalupensis …