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Biogeographic, Ecological, And Evolutionary Aspects Of South American Austral Migration, With Special Reference To The Family Tyrannidae., Robert Terry Chesser

LSU Historical Dissertations and Theses

South American austral migrants are bird species that breed in temperate South America in the southern summer and migrate north, towards or into northern South America, for the southern winter. Austral migration is similar to other avian migration systems in many ways, but its uniquely South American locale is reflected geographically by the relatively short-distance migrations of most austral migrants, and taxonomically by the numerical dominance of the suboscine family Tyrannidae (the tyrant-flycatchers), of which more than 70 species migrate. Detailed examination of the distributions of austral migrant flycatchers revealed that each is to some extent unique, but that discernible …

Biotic And Abiotic Factors That Affect The Development And Survival Of Cat Flea (Ctenocephalides Felis (Bouche)) Life Stages., William Joseph Lawrence Jr

LSU Historical Dissertations and Theses

Biotic and abiotic factors that affect the development and survival of cat flea (Ctenocephalides felis (Bouche)) life stages were studied. Adult feas maintained on an artificial host system exhibited high rates of mortality when provided with dog hair substrates washed in either hexane or soap and water. Delayed egg production for fleas provided with bovine blood containing Na Citrate concentrations $>$8 mM was observed. Fleas fed with Na Citrate concentrations $\ge$24 mM had an increase in blood consumption and mortality. Certain concentrations of testosterone fed to fleas either in steer blood or in an alternate blood meal were associated …

A Comparative Study Of The Ecology Of Smooth Flounder, Pleuronectes Putnami, And Winter Flounder, Pleuronectes Americanus, From Great Bay Estuary, New Hampshire, Michael Patrick Armstrong

Doctoral Dissertations

Smooth flounder, Pleuronectes putnami, and winter flounder, Pleuronectes americanus, co-occur in estuaries along the east coast of North America from Labrador to Massachusetts. Results of a three year sampling program indicated that the two species were partially segregated along salinity and depth gradients in upper Great Bay Estuary, New Hampshire. Along the salinity gradient, smooth flounder were most abundant at the oligo-mesohaline riverine habitat while winter flounder were most abundant at the meso-polyhaline open bay habitat. Both species exhibited a generalized up-river movement with seasonally increasing salinity. Smooth flounder showed ontogenetic changes in distribution along the depth gradient, with the …

Population Dynamics And Recruitment Ecology Of Some Caribbean Reef Corals, David B. Carlon

Doctoral Dissertations

Processes that limit the distribution arid abundance of marine species may affect larvae, juveniles, or adults. I focus on larval and early benthic phases of reef corals as determinants of spatial pattern. In CHAPTER I examine larval behavior during dispersal and settlement as a mechanism for aggregated spatial pattern in two corals. A short swimming period and non-selective settlement behavior explains the highly aggregated spatial pattern in Favia fragum. Spatial pattern in Agaricia agaricites probably reflects larval behavior at settlement and post-settlement mortality. These larvae had a longer planktonic period and were selective in settlement surfaces.

In CHAPTER II, I …

Molar And Local Effects Of The Fixed-Ratio Changeover Requirement On Choice, Changeovers, And Visits: A Parametric Examination Of The Fixed-Ratio Changeover Requirement, Michael B. Ehlert

Doctoral Dissertations

The distribution of behavior by organisms in choice situations is of long-standing interest to psychologists. The generalized matching relation accurately predicts choice between concurrent variable-interval schedules of reinforcement. Researchers have assumed, on weak grounds, that the effect of the changeover requirement on sensitivity to reinforcement--the exponent in the generalized matching equation--was consistent. This experiment considered the effects of the changeover requirement by parametrically manipulating the fixed-ratio schedule required to switch alternatives. Pigeons pecked either of two side-response keys in a standard three-key operant chamber for food, delivered according to independent variable-interval schedules. No changeover delay was used, instead completion of …

The Role Of Fecal Pellets In The Flux Of Carbon To The Sea Floor On A River-Influenced Continental Shelf Subject To Hypoxia., Naureen Aziz Qureshi

LSU Historical Dissertations and Theses

The Louisiana continental shelf near the Mississippi and Atchfalaya River deltas is a stratified and highly productive coastal system characterized by the largest hypoxic (dissolved oxygen $<$2 mg l$\sp{-1}$) zone in the western Atlantic Ocean. Carbon export from surface waters in the form of sedimenting zooplankton fecal pellets was examined to determine its importance in the formation and maintenance of oxygen deficiency in the bottom waters. Two sediment traps (5-6 and 15 m) were deployed in 1991 and 1992 in 20 m water depth within an area of chronic and seasonally severe hypoxia. I determined the fecal pellet number and carbon flux, and total carbon flux from the surface waters, the percent primary production exported as fecal pellets, and the potential for fluxed fecal pellet carbon to support bottom water hypoxia. I also quantitatively sampled the water column at discrete depths for fecal pellets and zooplankton to determine potential source organisms and their seasonal, diel and spatial variation. The highest densities of total organisms, copepods and copepod nauplii occurred during March and April (1992), when chlorophyll a concentrations in surface waters were highest, and decreased in summer and fall. The abundance of fecal pellets was positively correlated with total organisms, copepods and copepod nauplii, the likely source of fecal pellets. The fluxes of total particulate material, organic carbon, organic nitrogen, fecal pellet carbon and phytoplankton carbon varied similarly between seasons, and was lowest in summer and highest in spring. The fluxes were greater in 1991 than in 1992. Seasonal variations in fecal pellet number and carbon flux were positively correlated with indicators of high surface water productivity in 1991, but not in 1992. The flux of fecal pellets from surface to bottom waters accounted for 55% of the particulate material exported vertically, exceeded phytoplankton carbon fluxes, and was high enough to deplete the bottom water oxygen reserves in spring. The results support the hypothesis that the development of summer hypoxia is associated with the decomposition of organic matter accumulated in spring primarily by the sedimentation of a phytoplankton bloom via fecal pellets, and not as intact phytoplankton cells.

Behavioral And Chemical Ecology Of Formosan Subterranean Termites, Coptotermes Formosanus Shiraki., Jian Chen

LSU Historical Dissertations and Theses

Three colonies of Formosan subterranean termites collected from Lake Charles, Louisiana were not antagonistic towards each other, and three of five colonies collected from New Orleans, Louisiana also showed no aggression. Colonies collected from widely separated parishes, however, often showed antagonistic behavior towards each other. Workers provided food to soldiers from different but amicable colonies whether nestmate soldiers were present or not. Intercolonial mutual grooming also was observed. Furthermore, termites assisted other termites of the same colony or an amicable one in finding food. This assistance in finding food occurred when termites foraged underground or on the surface. Based on …

Impacts Of Irrigation Development On Anadromous Fish In The Yakima River Basin, Washington, Robert L. Tuck

All Master's Theses

Prior to Euroamerican development, the Yakima River Basin was a major producer of salmon. Total runs of approximately 800,000 have declined to 3,000-5,000, or less than 1% of original run size. Three species are extinct in the basin, including summer chinook, coho, and sockeye.

Irrigation development, including the construction of unscreened diversions, the blockage of spawning and rearing habitat by reservoir dams, and the dewatering of spawning and rearing habitat, began in the mid-1800's and today totals approximately 500,000 acres. Historical records provide a wealth of information documenting irrigation development and its consequences on anadromous fish populations.

Social Rank And Foraging Behavior In Rats: Effects Of Food Size, Density And Distribution, Maria Phelps

Digitized Theses

A number of field studies, conducted with birds, have found that dominant birds aggress against subordinate birds to attain priority of access to food. However, the level of aggression exhibited by dominant birds varied in accord with a cost-benefit analysis of the physical properties and spatial organization of the resource base. When the costs of aggression exceeded the benefits gained from resource defense, dominant birds decreased the level of aggression. Because rats also forage in groups and form functional social hierarchies, it was predicted that dominant rats, like dominant birds, would decrease aggression as a function of three resource attributes. …

Effects Of Industrial Effluents On Populations Of The Freshwater Mussel Lampsilis Radiata In The St Lawrence River, Lee Curtis Grapentine

Digitized Theses

The objective of this study was to assess the effects of industrial discharges, contaminated primarily with trace metals, on populations of Lampsilis radiata (Bivalvia: Unionidae) in the upper St. Lawrence River. Effects on shell growth were examined by (a) comparing growth curves derived from analyses of external annual rings of clams sampled from sites located upstream and downstream of four localized sources of discharges, and (b) measuring shell growth for one year from clams that were transplanted into contaminated and uncontaminated sites. Allozyme frequencies in clams from above and below discharges were determined for glucose-phosphate isomerase (GPI) and phosphoglucomutase (PGM), …

Teacher Resouce Guides For The San Bernardino County Museum, Cindy Louise Fullwiler

Theses Digitization Project

No abstract provided.