Physical Sciences and Mathematics Commons^™

Susceptibility Of Adult Colorado Potato Beetle (Leptinotarsa Decemlineata) To The Fungal Entomopathogen Beauveria Bassiana, Ellen Klinger

Electronic Theses and Dissertations

Factors influencing the susceptibility of adult Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), to the fungal entomopathogen, Beauveria bassiana (Bals.), were studied. In an assay comparing trials between a): laboratory reared, non-diapausing beetles and b): field collected, post-diapausing beetles, survival of B. bassiana treated beetles was higher for non-diapausing adults, however, control mortality was higher for post-diapausing adults. In a similar assay with field collected pre- and post-diapausing beetles, survival of B. bassiana treated individuals was higher for post-diapause adults and control mortality was higher for post-diapausing adults than pre-diapausing beetles. In a third experiment, the effect of time from …

Geographic Variation In The Morphology Of Crotalus Horridus (Serpentes: Viperidae), John Robert Allsteadt

Biological Sciences Theses & Dissertations

The Timber Rattlesnake (Crotalus horridus) occurs in discontinuous populations throughout the eastern and central United States. The species exhibits high levels of polymorphism in morphological traits, especially in coloration and pattern. Previous studies recognized either distinct northern and southern subspecies or three regional morphs (northern, southern, and western), but conflicting data sets and limited geographic sampling of previous studies have left the relationships among those regional variants unclear. In this study, univariate and multivariate statistics, together with a geographic information system, were used to analyze geographic variation in 36 morphological characters recorded from 2,420 specimens of C. horridus …

Travel Time Study At The Wetlands Park National Preserve, Brandon Bair

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis reports on a study of the residence time of water in the Wetlands Park Nature Preserve in Henderson, Nevada. Rhodamine WT was used in order to test for the travel time of the water from the Monson Channel inflow to the Nature Preserve outflow to the Las Vegas Wash. The initial hypothesis was that the water would stay in the system for approximately 8 days. Residence time was tested using an ISCO sampling machine along with a Sequoia-Turner model 450 fluorimeter to test for the fluoresce of the dye in the water. All samples collected were taken immediately …

Analysis Of The Effects Of Hypogeal And Epigeal Emergence On Seedling Competition In Legumes, Keith E. King

McCabe Thesis Collection

Seedling emergence is either hypogeal or epigeal. In hypogeal emergence the cotyledons remain below the soil surface during seedling development, while in epigeal emergence the cotyledons extend above the soil surface due to elongation of the hypocotyl. Here we examine the effect of seed size, and emergence type, on seedling growth. Six legumes with variation in seed size and either epigeal or hypogeal emergence were grown under dark and light conditions. A competition study was also conducted where a hypogeal and epigeal legume were grown in combination with wheat and ryegrass. Legumes expressing epigeal emergence were cowpea (Vigna unguiculata), mung …

Fluctuations In Chinook Salmon (Oncorhynchus Tshawytscha) Counts At Three Lower Columbia River Spawning Sites, Eric Michael Loomis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several hypotheses were developed to explore the pronounced increase in Chinook salmon (Oncorhynchus tshawytscha) returning to spawning grounds at the Cowlitz, Kalama, and Lewis Rivers, three tributaries of the lower Columbia River. The study was conducted using data compiled over a ten-year span from 1991-2001. Preliminary indications are that trends in climate are linked to these increases, with the absence of El Niño events and fluctuations in winter precipitation as likely explanations of these phenomena. The unique nature of Chinook life cycles causes them to utilize a variety of habitats that require ideal conditions for maximum survival rates. Correlations between …

The 100th Meridian Initiative In Nevada: Assessing The Westward Movement Of The Zebra Mussel To The Lake Mead National Recreation Area, Megan Mccoy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zebra mussels, Dreissena polymorpha, are a concern for all bodies of water in North America. East of the 100th Meridian, zebra mussels have infested the waters and dramatically changed the natural ecosystems. The US Fish and Wildlife Services set up the 100th Meridian Initiative project to monitor the boat traffic to and from infested and non-infested waters of the United States and Canada. Surveys were conducted from October 19, 2002 through March 31, 2003, focusing specifically on the Lake Mead National Recreation Area (LMNRA) for the scope of this thesis. This study addresses the movement of trailers, boats, and other …

Population Dynamics And Spatial Analysis Of The Maine Green Sea Urchin (Strongylocentrotus Droebachiensis) Fishery, Robert C. Grabowski

Electronic Theses and Dissertations

Fisheries research on the green sea urchin in Maine has been limited despite its importance to the state's fishing industry. The objective of this thesis was to generate critical information for the management and monitoring of the Maine green sea urchin fishery. In particular there are three main areas of interest: (1) an investigation of biological reference points; (2) spatial analysis and biomass estimation, and (3) the development of a simulation framework approach to determine an optimal sampling strategy for the fishery-independent survey program. Biological reference points are markers conlrnonly used to monitor and manage fisheries. For the Maine sea …

Modeling Bird Species Occurrence In Current And Future Landscapes, Stephen Nicholas Matthews

Electronic Theses and Dissertations

With mounting evidence that global temperatures have increased significantly over the last century and the projections of greater changes in climate by the end of this century, understanding the potential consequences of these changes for species is essential to conservation efforts. Here I evaluate the potential response of birds to projected climate change by using regression tree analysis to create models of species distributions under current conditions from Breeding Bird Survey data and then project these models onto General Circulation Model (GCM) scenarios of global climate change. Before modeling species responses to climate change, I selected seventeen bird species to …

Determining The Factors That Control Respiration And Carbon Use Efficiency In Crop Plants, Jonathan M. Frantz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the literature on plant respiration, there are two viewpoints concerning the source of respiratory control: supply (photosynthate availability) or demand (temperature dependent) limitations. While different studies indicate the primary dependency for respiration is either the supply or demand side, the two paradigms cannot both be true. The relative importance of each paradigm may depend on a number of factors including period of time during which respiration is measured, phase of plant development, environmental conditions, and species.

Studies were performed using continuous CO₂ gas-exchange instrumentation to monitor short- and long-term changes in whole canopies of lettuce, tomato, soybean, and …

Modeling Habitat Quality For American Martens In Western Newfoundland, Canada, William A. Adair

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The "Den Mother" marten habitat quality models were created to provide insight into American marten habitat selection behavior and to promote the recovery of the Newfoundland marten (Martes americana atrata) population. Although these objectives are typical of most wildlife habitat modeling projects, the marten's idiosyncratic habitat ecology and apparently intractable conflicts associated with timber harvesting motivated a unique, process-oriented approach to appraising landscapes. The Den Mother models used optimal decision-making principles to synthesize critical resources (den sites and foraging opportunities) and constraints (adverse thermal situations and exposure to predations) into a single hierarchical framework. The resulting spatially explicit, …

Breeding Bird Communities Of Major Mainland Rivers Of Southeastern Alaska, Jim A. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Because of the scarcity of information for bird communities at the major mainland rivers of southeastern Alaska, the main objective of this study was to provide baseline information including distribution, status, and habitat associations of breeding birds.

I conducted a meta-analysis of all known reports (including the current study) conducted at major mainland rivers during the breeding season. I described bird species composition, distribution, abundance estimates, status, habitat associations, and guild membership for all birds recorded at 11 major mainland rivers. Based on incidental observations, 170 species were recorded by all studies. Of these, 134 species were known or suspected …

The Use Of Acoustics To Resolve Nightly Excursions Of Hyperbenthos, Heather U. Abello

Electronic Theses and Dissertations

Acoustic analysis of die1 vertical migration in the Darnariscotta River estuary, Maine, showed a fairly regular nightly increase in biovolume (mm3 m'3) of organisms in the water column, presumed to be due to emergence, the entry of hyperbenthic organisms into the water column. Timing of these events was significantly correlated with time of sunset and time of sunrise for more than 50% of the dates where emergence and re-entry could be identified, between June and October 2002. Emergence traps indicate that the mysid shrimp, Neomysis americana, is the predominant migrator. Daily fluctuations in irradiance influence the timing of emergence fiom …

Scope For Activity, Specific Dynamic Action And Growth In Early Juvenile Stages Of Atlantic Cod, Gadus Morhua, Sorren Lund Hansen

Electronic Theses and Dissertations

Growth rates of early life stages of Atlantic cod (Gadus morhua) are very high, but decline, as the fish grow larger. Little is know about the physiological processes that facilitate and regulate this growth pattern. In this study, feeding and swimming metabolism were measured in individual juvenile Atlantic cod (Gadus morhua) in order to investigate how energy are allocated to swimming and growth in fast growing stages of fishes. Metabolic rates were measured by the means of oxygen consumption using two "Brett-type" respirometers. The metabolic measurements were repeated several times in individual juvenile Atlantic cod with a wet body mass …

Lipid Solubilization By Marine Benthic Invertebrates, Ian M. Voparil

Electronic Theses and Dissertations

This work characterized the size of lipoidal colloids in benthic invertebrates' guts, using contact angle dilutions and imaging the fluorescence of the hydrophobic probe Nile Red. Deposit feeders and Nereis virens ingesting sediment were found to have micelles rather than emulsions in the gut. Gut fluids from Arenicola manna (a deposit-feeding polychaete) readily formed emulsions when incubated with mussel meat (Mytilus edulis; 80 g-mussel L"-gut fluid), suggesting that micelles form due to a paucity of emulsifying lipids in the gut. Lipid tracer contained in emulsion droplets was twice as likely to be captured by sediment than was tracer in micelles. …

The Short And Long-Term Effects Of Herbicide Application In Maine Clearcuts On Ant Communities (Hymenoptera: Formicidae), Kerry Frances Lough

Electronic Theses and Dissertations

The short and long-term effects of glyphosate application on the diversity and abundance of ants in Maine clearcuts was assessed in a two-year study. Glyphosate is applied to release coniferous trees from suppression by competition with deciduous vegetation after a forest is clearcut. Previous research indicates glyphosate has limited immediate and long-term effects on non-target fauna, though specific species can be affected. Limited research on the effects of herbicides on insects indicates some initial decrease in insect populations. Beneficial insects, such as pollinators and predators, positively influence the forest ecosystem, but little research has examined the effects of herbicide application …

Field Testing Of Abrasion Resistant Carbides, Kevin C. Orme

Undergraduate Honors Capstone Projects

Chromium, tungsten, titanium, and vanadium carbides were investigated to determine relative cost of operation for each in an agricultural environment. For use on a ripper plow, these carbides were field tested in two different soil types; one soil having a matrix of gravel and cobblestones, and the other consisting of hard dirt and large underground rocks. Each alloy was applied to a high carbon plow point using an arc welding process. Along with the welded points, cast chromium carbide was tested. The results are given in price per acre and not solely longevity of the point. It was concluded that …

An Analysis Of Materials Suitable For Use As A Pitfall Trap In A Desert Environment, R. Renee Brown

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to identify a type of pitfall trap container that can withstand the temperature extremes of the Mojave Desert in which the terrestrial, or above ground, drift fence with pitfall traps will be utilized for trapping reptiles. A pitfall trap is a container, such as a plastic bucket with a plastic lid, that is buried in the ground up to the lip of the bucket and used to catch small ground dwelling fauna that fall into the trap. Many different pitfall trap materials have been utilized in the trapping of small ground-dwelling fauna. Plastic has …