Zoology Commons^™

Ecology Of The Eastern Cottonmouth (Agkistrodon P. Piscivorus) At Back Bay National Wildlife Refuge: A Comparative Study Of Natural And Anthropogenic Marsh Habitats, Chad Lee Cross

Biological Sciences Theses & Dissertations

Mark-recapture sampling and radiotelemetry were used to investigate populations of the eastern cottonmouth, Agkistrodon p. piscivorus, in both natural and anthropogenic marsh habitats at Back Bay National Wildlife Refuge (BBNWR), Virginia Beach, Virginia from autumn 1995 to late spring 1998. Mark-recapture subjects were captured, marked by ventral scale-clipping, and released back into the population. A modified Schnabel Census estimator was used to estimate population sizes and corresponding densities in both marsh systems based on a total of 244 captures of 222 individuals. Most snakes were found >0.05 in from water, but it was apparent that proximity to water played …

The Annual Reproductive Cycle Of Oryzomys Palustris In A Virginia Tidal Marsh, Erin A. Dreelin

Biological Sciences Theses & Dissertations

The objectives of my study were to determine when the marsh rice rat (Oryzomys palustris) begins and ends reproduction during the year, if there are seasonal changes in litter size, and the weight at which sexual maturity is reached. Monthly samples of rice rats were trapped from May 1995 to May 1996 in Northampton County, Virginia. Rice rats were trapped with Fitch live traps, euthanized in the field, and brought to the lab for necropsy. Data from two other studies of rice rats in Northampton County were also examined. Potential breeders did not reproduce with equal intensity throughout the …

Systematics Of The Freshwater Amphipod Genus Crangonyx (Crangonyctidae) In North America, Jun Zhang

Biological Sciences Theses & Dissertations

The systematics of the amphipod genus Crangonyx of North America (north of Mexico) is revised, based on available collections (ca. 2240) and literature dealing with the genus. A grand total of 42 North America species of Crangonyx are recognized in the present study, 24 of them new to science. All species are described or redescribed and figured, utilizing external morphological features. Keys to both species groups and individual species are given. Phylogenetic trees are built using computer programs (PAUP, Hennig86, MacClade) based on 26 characters. Wagner parsimony produced 18 parsimonious trees and Fitch parsimony produced 45 trees. The consensus tree …

Ecological Relationships Between The Marsh Rice Rat (Oryzomys Palustris) And The Meadow Vole (Microtus Pennsylvanicus) In Two Virginia Tidal Marshes, Christopher P. Bloch

Biological Sciences Theses & Dissertations

Small mammals were trapped for 23 months on two live trap grids in tidal marshes in Northampton County, on the Eastern Shore of Virginia, to examine ecological relationships between the marsh rice rat (Oryzomys palustris) and the meadow vole (Microtus pennsylvanicus). Population density, survival rates, capture probability, recruitment, residence time, and home range size were calculated for each species. Patterns of reproductive activity and fluctuations in mean weight were also observed.

There were considerable differences in population dynamics between the two sites. At Grid 2, where vegetative cover was more abundant, population densities of rice rats and meadow voles …

Ecology Of The Early Life History Of The Caribbean Spiny Lobster, Panulirus Argus: Recruitment, Predation, And Habitat Requirements, Charles A. Acosta

Biological Sciences Theses & Dissertations

Recruitment variability of the early life history stages of marine benthic organisms can have profound consequences on population dynamics. I studied factors affecting recruitment success of postlarvae and early juveniles of the Caribbean spiny lobster. I examined patterns in postlarval supply, investigated wind forcing as a potential transport mechanism for recruiting postlarvae, and quantified predation on postlarvae in south Florida, USA. In an eight-year time series, spiny lobster postlarval supply occurred year-round between the new and first quarter lunar phases. The major annual peak occurred around March corresponding to spawning activity ten months earlier, and a smaller non-seasonal peak occurred …

The Diet Of Oryzomys Palustris Based On Stomach Content Analysis, Shannon L. Wright

Biological Sciences Theses & Dissertations

Oryzomys palustris (Harlan) is unusual in that it is one of two carnivorous mammals in the Family Muridae in North America. A diet analysis of Oryzomys palustris. the marsh rice rat, was done based on stomach contents. This was accomplished by taking the animals from two study areas located on the Eastern Shore of Virginia. The animals were taken monthly for one year. Once caught, the animals were sacrificed and their stomach contents were identified to the lowest taxonomic level possible. This study showed that rice rats were omnivorous mammals, eating a variety of foods, including dicots, monocots, crabs, …

Movement Patterns And Habitat Use Of The Copperhead Snake (Agkistrodon Contortrix) In Southeastern Virginia, Christopher Edwin Petersen

Biological Sciences Theses & Dissertations

Radiotelemetry was used to study seasonal movement patterns, habitat use, and thermal relations of nine copperhead snakes, Agkistrodon contortrix, in southeastern Virginia from May 1993 to May 1995. Daily movements ranged from 0-450 m, with 0-5 m movements accounting for 65% of the observations. The seasonal movements of males were more extensive than those of females. Differences in seasonal movements between the sexes may be due to reproductive activity of the snakes. Both males and females significantly reduced their movements prior to shedding. More time was spent using upland deciduous forests than lowland river swamps or anthropogenic habitat. Copperheads …

The Distribution Of Rice Rats (Oryzomys Palustris) And Meadow Voles (Microtus Pennsylvanicus) In Tidal Marsh Communities On The Eastern Shore Of Virginia, Allison L. Sowell

Biological Sciences Theses & Dissertations

Two tidal marsh sites were selected for live trapping of small mammals on the Eastern Shore of Virginia. Trap grids were established at site and animals were trapped and tagged each month for one year. Habitat variables were measured at the peak of the growing season and again in late winter when vegetation was at its least luxuriant. ANOVA and multiple regressions were used to analyze the relationships between rice rats and meadow voles and associated variables related to habitat structure.

ANOVA revealed where rice rats and meadow voles differed in habitat preferences. Meadow voles were consistently captured in association …

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus On The Eastern Shore Of Virginia, John A. March Jr.

Biological Sciences Theses & Dissertations

The population dynamics of Oryzomys palustris, the marsh rice rat, and of Microtus pennsylvanicus, the meadow vole, were determined during a year-long mark-and-recapture study on the Eastern Shore of Virginia. Three nights of trapping per month were conducted on two live trap grids totaling 5456 total trap nights. The grids were located on Nature Conservancy land, one in Oyster, and the second at Steelman's Landing, which is east of Townsend in Northampton County Virginia. Trapped animals were evaluated using established criteria. Reproductive activity, age and sex composition, and density of the population, capture probability, survival rate, and recruitment were determined. …

Demography, Reproduction, Diet And Crop Depredation In Three Species Of Rodents In Natural And Irrigated Fields In Nigeria, Safianu Rabiu

Biological Sciences Theses & Dissertations

Rodent populations of Arvicanthis, Mastomys and Tatera were studied during July 1990 to August 1992 in both natural and irrigated savannah fields of northern Nigeria. Tatera was entirely absent from the irrigated fields. Irrigation enhanced higher rodent population densities in the magnitude of three to four times over densities in the natural field. Arvicanthis was the most abundant of the three species in both sites. Tatera was the least common in the natural site. Adult survival rates in Arvicanthis and Tatera were significantly higher than Mastomys. Survival rates of both adult and young differed between the wet and dry …

The Effect Of 6-Methoxybenzoxazolinone On Reproductive Condition In The Hispid Cotton Rat, Sigmodon Hispidus, Vera Lee Adams

Biological Sciences Theses & Dissertations

A non-estrogenic hormone, 6-methoxybenzoxazolinone (6-MBOA), found in young growing grasses, has been shown to be a reproductive initiator in several herbivorous rodents. However, the mechanism by which 6-MBOA initiates reproduction has not been determined. Many believe that 6-MBOA represents a reliable cue that the vegetative growing season has begun, but it is unknown whether this hormone is a primary cueing mechanism or if it works in conjunction with other environmental factors. Therefore, a controlled laboratory experiment was conducted using male and female Sigmodon hispidus, the hispid cotton rat, to determine whether different dosages of 6-MBOA (4μg, 40 …

Evaluation Of The Gross Anatomy Seasonal Changes Function And Histology Of The Perineal Gland In The Hispid Cotton Rat, Sigmodon Hispidus, Julie Anne Winchell

Biological Sciences Theses & Dissertations

The perinea! gland in the hispid cotton rat, Sigmodon hispidus, is a seasonally cyclic, subcutaneously located organ which is associated with the reproductive system. On gross dissection, the gland possesses a strong attachment to the penis with only loose fascia! connections to the rectum and surrounding muscle and skin. Histologic exam confirms this connection to the reproductive tract and shows the organ to be a compound tubuloacinar gland with a projection leading into the penis. The cyclic hypertrophy and regression of the gland closely parallels that of the testes and seminal vesicles indicating that this cyclicity may be under …

Pheromonal Composition Of Two Species Of African Amblyomma Ticks: Similarities, Differences And Possible Species Specific Components, Thomas Lem Price Jr.

Biological Sciences Theses & Dissertations

Two species of bont ticks, Amblyomma hebraeum and Amblyomma variegatum, common to Africa have been studied to compare types and quantities of compounds known or believed to serve as components of the attraction-aggregation-attachment pheromone (AAAP). A complex of attraction, aggregation and attachment pheromones are used by these ticks to detect hosts, mates and perhaps minimize interspecific breeding. Solvent extraction of pheromone emitting ticks followed by Gas Chromatography and Mass Spectrometry revealed little difference in the composition of the AAAP in these two species. However, subtle differences in the relative makeup of the pheromonal blend are noted, suggesting that such differences …

Seasonal Changes In Brown Adipose Tissue And Pelage Of The Southern Short-Tailed Shrew Blarina Carolinensis, Elisa Michelle Dew

Biological Sciences Theses & Dissertations

Winter survival mechanisms in the southern short-tailed shrew, Blarina carolinensis, were studied by examining cellular changes in interscapular brown adipose tissue (ISBAT) and pelage characteristics in specimens collected each month of the year in eastern Virginia. On capture, each specimen was anesthetized with ether and then perfused with a 2.5% glutaraldehyde-2% formaldehyde solution. ISBAT tissues were examined histologically with the transmission electron microscopy. Because BAT is know to produce heat by nonshivering thermogenesis and is more developed in winter animals than summer animals, it was hypothesized that mitochondrial area of BAT would be relatively greater in winter than in summer. …

Population Dynamics Of Feral House Mice And Meadow Voles On A Dredge Disposal Site, Georgia E. Kratimenos

Biological Sciences Theses & Dissertations

The population dynamics of two species was studied for one year on Craney Island in Portsmouth, Virginia. This dredge disposal site provided good habitat for the house mouse, Mus musculus, whose opportunistic behaviors can withstand the sudden changes in a dynamic environment. Although the site was not optimal habitat, a population of Microtus pennsylvanicus, the meadow vole, was sustained there. Of the seven species of small mammals captured, 65% were house mice and 28% were meadow voles. Meadow voles were more successful at establishing short periods of residency than were house mice; on average, each meadow vole was …

The Identification, Distribution, And Status Of The Threatened Dismal Swamp Shrew (Sorex Longirostris Fisheri), Thomas M. Padgett

Biological Sciences Theses & Dissertations

Southeastern shrews (Sorex longirostris) were trapped throughout southeastern Virginia and northeastern North Carolina to determine if any morphological characters could

be identified that would aid in the identification and distribution of the threatened subspecies Sorex l._ fisheri, endemic to the Great Dismal Swamp, the more upland nominate subspecies Sorex l. longirostris, and possible intergrades between the two subspecies. Animals were classified a priori into three groups, based on their location of capture. Animals collected from the Great Dismal Swamp National Wildlife Refuge (GDSNWR) and associated bottomland habitats were designated as "fisheri", animals collected farthest from the Swamp as "longirostris", and …

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …

Comparison Of The Protein Content In Selected Tissues At Different Feeding Stages In The American Dog Tick Dermacentor Variabilis (Say), Mark John Beveridge

Biological Sciences Theses & Dissertations

Selected tissues from Dermacentor yariabilis (Say) were collected at different feeding stages (unfed, part-fed, and replete) and examined by several different protein analyses to determine soluble protein content, protein or polypeptide molecular weights, and pI values. Results showed a relationship between the salivary gland, ovary and hemolymph and evidence indicates the synganglion produces and secretes substances that may control oocyte development.

Investigations Of The Trophic Relationships, Feeding Ecology And Feeding Behavior Of Larval Spot, Leiostomus Xanthurus Lacepede, And Atlantic Croaker, Micropogonias Undulatus (Linnaeus) (Pisces:Sciaenidae), Dirk Edward Peterson

Biological Sciences Theses & Dissertations

The feeding ecology of preflexion and flexion-postflexion spot (Leiostomus xanthurus) and Atlantic croaker (Micropogonias undulatus) larvae was evaluated and compared. Nutritional condition of spot larvae from the Gulf of Mexico was high, with no larvae classified as starving. This was probably due to an inability to sample starving larvae at sea because of predation pressure or was indicative of favorable feeding conditions and an absence of starvation in the collection area. In spite of morphological similarities between the species, significant differences in body shape existed.

The diets of the two species converged with age and interspecific dietary overlap was relatively …

The Development And Comparative Morphology Of The Mandibular Symphysis In Salamanders, Jennifer Lorenz Elwood

Biological Sciences Theses & Dissertations

Despite the extensive literature on salamander cranial morphology, few authors mention the structure or development of the mandibular symphysis. Adult specimens representing eight caudate families and larval Ambystoma opacum, representing nine developmental stages, were evaluated histologically to determine the structure and development of the mandibular symphysis.

From this analysis it was determined that early in the ontogeny of the mandibular symphysis Meckel's cartilages are separated by a band of undifferentiated cartilage. As development progresses, this band of undifferentiated cartilage gradually transforms into a wedge of fibrocartilage which fuses to Meckel's cartilages.

Symphyseal morphologies of the adult caudates could be broken …

A Light And Electron Microscopic Study Of The Rat Olfactory Tubercle: Normal Morphology And Acetylcholinesterase Localization, James Curtis Woodley

Biological Sciences Theses & Dissertations

A cytoarchitectural analysis of the rat olfactory tubercle using Nissl-stained coronal sections revealed that the dense cell layer (DCL) consisted of medium sized striatal cells in the cortical regions and small sized "granule" cells in the cap regions. Also delineated from this experiment was a rim of neuropil, nearly devoid of neurons as well as neuronal processes, outlining the islands of Calleja. Acetylcholinesterase (AChE) localization utilizing light microscopy revealed that the olfactory tubercles (OT) contained AChE-positive fibers that were orientated dorsoventrally in the molecular and multiform layers. The DCL consisted of only fibers en passant and putative terminals. Diisopropylfluorophosphate (DFP) …

Environmental Factors Affecting Nocturnal Migrations Of Macrobenthos, C. Timothy Morris

Biological Sciences Theses & Dissertations

Nocturnally dispersing macrobenthic invertebrates of the Lafayette River, Norfolk, Virginia were collected from September 4 to October 4, 1982 to determine environmental factors affecting migrations. A total of 55 taxa were identified from 325 surface and bottom nocturnal plankton tows. Peracaridan crustaceans were the dominant (99.0% of the total density) group collected. Six of the commonly collected species showed a significant (P

The Relationship Between Habitat Structure And Small Mammal Communities In Southeastern Virginia And Northeastern North Carolina, Roger Keith Everton

Biological Sciences Theses & Dissertations

A variety of terrestrial habitats was pitfall trapped in the vicinity of the Great Dismal Swamp of eastern Virginia and North Carolina to evaluate the small mammal community within the region. Habitat variables were measured at the end of the growing season on 21 0.25 ha grids. Four multivariate tests were used to examine the small mammal communities, their relationship with habitat structure, and the role of habitat selection in community structure.

Cluster and ordination analysis revealed the existence of two distinct associations of small mammals, and their habitat types, within the region. The small mammal associations were interpreted as …

Demographic Analysis And Microhabitat Relationships Of A Small Mammal Community In Clearings Of The Great Dismal Swamp, Jean Ferguson Stankavich

Biological Sciences Theses & Dissertations

Small mammals were trapped for 14 months on two grids located within a powerline right-of-way in the Great Dismal Swamp National Wildlife Refuge. During 12,354 trap nights, individuals of 10 different species were captured. They included, from highest to lowest density, Reithrodontomys humulis, Ochrotomys nuttalli, Peromyscus leucopus, Blarina brevicauda, Synaptomys cooperi, Microtus pennsylvanicus, Microtus pinetorum, Sigmodon hispidus, Mus musculus and Oryzomys palustris. The demography (densities, reproduction, home range and dispersal) of each species was analyzed when possible. Most of the species were present in relatively low densities, with a number being captured only during the latter months of the study. …

Life History Aspects Of Reithrodontomys Humulis In Southeastern Virginia, Michelle Cawthorn Chandler

Biological Sciences Theses & Dissertations

Reithrodontomys humulis, the eastern harvest mouse, is a small cricetid rodent which is common in old field communities in the eastern U.S. A live-trapping study was conducted in Suffolk, Virginia from March 1983 through February 1984 in order to learn the details of its life history and the vegetational characteristics which best describe its microhabitat. Specifically, population densities, trap-revealed survival times, home ranges, plant species composition of the study area, and vegetational structure were examined. In order to trap as many Reithrodontomys as possible, special traps which excluded animals weighing over 20 g were constructed. Densities of harvest mice …

Activity Levels Of Arboreal Rodents Peromysus And Ochrotomys Evaluated With Nest Cans In Seasonally Flooded Forests, John W. Walke

Biological Sciences Theses & Dissertations

The diversity and density of small mammals in the Dismal Swamp are believed to be small. To test this, four 1.96 ha grids were established and operated in the Dismal Swamp National Wildlife Refuge, from September 1981 to November 1982. Number 10 metal cans covered with plastic lids were placed as nest boxes at 0.5 to 1.5 m height on trees. A 2.5 cm hole allowed access by arboreal rodents, to each nest can. The activity level of the two arboreal rodents, Peromyscus leucopus and Ochrotomys nuttalli, was evaluated by observing types of activity ranging from presence of mice to …

Characterization Of The Dna And Chromosonal Analysis Of Embryonic Dermacentor Variabilis (Say) Cells In Culture, Stanley Nicholas Mason

Biological Sciences Theses & Dissertations

Cultured embryonic Dermacentor variabilis cells were examined by spectrophotometric techniques to determine total cellular DNA concentration and guanine-cytosine content of the DNA and by differential staining procedures to define the karyotype further. The cells were found to have a mean DNA content of 16.98 pg and a DNA guanine-cytosine content of 49%. Chromosome banding attempts resulted in the specific characterization of four chromosomes and differential grouping of the seven remaining chromosomes. A previously unreported submetacentric chromosome was identified.

Homing And Ecology In The Southern Flying Squirrel, Glaucomys Volans In Southeastern Virginia, Sherrie Lynn Sawyer

Biological Sciences Theses & Dissertations

The purpose of this study was to determine whether homing occurred in the southern flying squirrel, Glauaomys volans, and if so, the greatest homing distance. Information on the squirrel's ecology, reproductive biology and use of artificial nest boxes was also obtained. The study was conducted from November 1978 through March 1981, using nest boxes placed in a deciduous forest in southeastern Virginia.

For the homing experiments, twenty squirrels were released a total of 29 times along three lines at distances of 250 m to 1.6 km from the homesites. Squirrels were found to home successfully up to 1,000 m.

The …

Food Habits And Ecology Of Beavers In Southeastern Virginia, John Lennox Echternach Jr.

Biological Sciences Theses & Dissertations

The food habits and ecology of three beaver colonies in James County, Virginia were studied. Vegetation surrounding the colonies was characterized as southern mixed hardwood forest or lowland swamp forest. Stream flow values ranged from 0.013 to 0.369 m³/sec. Water depth ranged from 0.5 60 4.0 m. Caloric value of 13 heavily used woody species ranged from 3305 to 6204 cal/g. Considerable seasonal variation was noted in most species with the lowest caloric values noted in summer. No relationship was found between caloric value and frequency of use. Fresh cutting was monitored on a weekly basis and a …

Incorporation Of Carbon-14 Metabolites Into The Sex Pheromon 26-Dichlorophenol Of Dermacentor Andersoni Stiles; And The Disruption Of Pheromone Activity In D. Andersoni And D. Variabilis (Say) By Quinones, Daniel Martin Gainsburg

Biological Sciences Theses & Dissertations

The Rocky Mountain wood tick, Dermacentor andersoni Stiles, injected with (u-¹⁴c) sodium acetate or DL-(benzene ring-u-¹⁴c) tryptophan for in vivo studies, was found to produce sex pheromone, 2,6-dichlorophenol, containing ¹⁴c activity. Ambiguous results were obtained with L-(u- ¹⁴c) tyrosine, and no incorporation of ¹⁴c label into pheromone was observed with DL-(ring-u- ¹⁴c) phenylalanine or DL-(side chain-3-¹⁴c) tyrosine. Attempts were made to determine the site of synthesis, but in vitro studies proved inconclusive.

Disruption of sex pheromone activity in D. andersoni and the American dog tick, D. variabilis (Say) was achieved …