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Population Structure And Phylogenetic History Of The Lake Malawi Cichlid Species Flock, Jeffrey Alan Markert

Doctoral Dissertations

The cichlid species "flocks" which are endemic to the East African Rift Valley are characterized by frequent lineage splitting events which have led to the rapid evolution of high levels of taxonomic diversity. Changes in water level cause these habitat patches to be chronically unstable, hypothetically speeding the process of genetic differentiation through the combined effects of genetic drift and selection. Allele frequencies at four simple sequence repeat loci indicate low levels of gene flow in two rock dwelling fish species, Melanochromis auratus and Labeotropheus fuelleborni, collected from the Nankumba Peninsula in southern Lake Malawi. Small interruptions in habitat cause …

Molecular Systematics Of Selected Members Of The Black Basses, Genus Micropterus, With Concentration On The Spotted Bass (M. Punctulatus) Species Complex., Belinda Fuller

LSU Historical Dissertations and Theses

This study examined genetic relationships among selected populations of black basses. These centrarchid fishes, separated by both physical barriers (land formations) and distance, have shown varying degrees of differentiation, but retain many morphometric characters in common. Eight populations representing four taxa and geographical extremes in the genus Micropterus, with concentration on the spotted bass complex, were selected and evaluated for biochemical genetic characters. This study examined two species and two subspecies of spotted basses. The type species from Kentucky represented Micropterus punctulatus punctulatus; a population from Alabama represented M. p. henshalli. A Texas population, previously classified as conspecific with spotted …

A Review Of The North American Squalodontidae (Mammalia, Cetacea)., Alton Cline Dooley Jr

LSU Historical Dissertations and Theses

All available North American specimens of squalodont whales were examined to determine species assignments, and to determine functional aspects and ecological implications. Only two existing species of the 17 referred to Squalodontidae from North America are members of that family, Squalodon atlanticus and Squalodon calvertensis. Of these two species, only S. calvertensis is based on adequate material for consideration as a valid species. Squalodon calvertensis is redescribed, based on the material which has been collected since 1923. These specimens indicate that the species is found from New Jersey to North Carolina, in the Miocene Kirkwood, Calvert, and Pungo River Formations. …

Effect Of Artificial Flooding On The Vegetation And Avifauna Of Riparian Woodlands At Santa Ana National Wildlife Refuge, Hidalgo County, Texas, Charles David Castillo

Theses and Dissertations - UTB/UTPA

Riparian habitats along the Rio Grande at Santa Ana National Wildlife Refuge have dramatically decreased since the construction of Falcon Dam in 1953. Riparian habitats are dependent on annual or periodic flooding to maintain their biological integrity. Lack of seasonal flooding has contributed to changes in vegetative composition from riparian forests to thornscrub. Effects of artificial flooding on vegetation and avifauna of riparian woodlands were evaluated from 1995-1997 at the Santa Ana National Wildlife Refuge. Floodwaters caused the destruction of all existing herbaceous species along study transects and the regeneration of new and native seedlings. Avian abundance and diversity dramatically …

Relative Rates Of Molecular Evolution In Rodents And Their Symbionts., Theresa Ann Spradling

LSU Historical Dissertations and Theses

The focus of this dissertation is the relative tempo of molecular evolution among organisms of varying levels of relatedness. Because this is a rapidly expanding area of research, Chapter 1 is devoted to a review of the current state of knowledge on rates of molecular evolution. In Chapter 2, I present an analysis of relative rates of evolution among several distantly related rodents. The heterogeneity in rate of evolution of the cytochrome b gene observed here cannot be explained by metabolic rate, body size, generation time, or nucleotide-generation time. Likewise, there is no evidence that these differences in rate of …

Predation By Nucella Lapillus (Linnaeus, 1758) On Littorina Obtusata (Linnaeus, 1758) And Mytilus Edulis (Linnaeus, 1758), Helena Matthews Cascon

Doctoral Dissertations

Prey preference and recognition by individuals of Nucella lapillus from 13 different populations from New England were studied, to determine if individuals of this species kept on a single prey diet develops a preference for this prey, and if prey availability affects prey recognition in this predator. Individuals from all 13 populations showed a preference for Mytilus edulis over Littorina obtusata in laboratory experiments, including those from a population that prey only on L. obtusata in the field. Individuals from another population were not able to recognize L. obtusata as a prey. N. lapillus kept in a diet of M. …

Variation In Reproductive Success Within A Natural Population Of The American Toad (Bufo Americanus), Paulo Cascon

Doctoral Dissertations

The purpose of this study was to investigate if mating success and clutch size are good estimates of reproductive success in a population of Bufo americanus, through the study of the contribution of life history parameters to the variation in individual reproductive success. A B. americanus population that breeds in a pond located in Madbury, NH was studied during the 1994, 1995 and 1996 mating seasons. In 1995 and 1996 clutches were also studied and the larvae were used in laboratory and field experiments. The following fitness parameters were investigated: mating success, clutch and egg size, growth rate and survivorship …

Neuroethology Of The Swimming Behavior In The Pacific Nudibranch, Melibe Leonina, Kathryn Ann Lawrence

Doctoral Dissertations

Melibe leonina is a subtidal nudibranch which is found in association with eelgrass and kelp. Melibe swims when disturbed, or knocked off of its substrate, by slow lateral undulations. Swimming is stereotyped in its form and execution, and can be reliably reproduced in the laboratory. Swimming consists of phases: (1) withdrawal, (2) flattening, (3) lateral flexions, (4) unfolding and swinging and (5) termination. Swimming can be reliably elicited using 1M KCl or contact with the tube feet of the predatory seastar Pycnopodia helianthoides. The duration of a single swim cycle and the amplitude of swimming flexions remain relatively constant, however, …

Foraging Strategies Of Two Sympatric Lagomorphs: Implications Of Habitat Fragmentation, Douglas Foxall Smith

Doctoral Dissertations

I studied the effects of variation in food patch quality and predation risk on the foraging patterns and measures of foraging behavior of New England (S. transitionalis) and eastern (S. floridanus) cottontails, and their survivorship and weight change during these experiments. I then superimposed the results of these experiments onto real habitat patches to determine the amount of habitat each species could occupy and maintain similar survivorship. Finally, I measured an adaptation (eye size), and predator detection of both species in an effort to explain the difference in survival between S. floridanus and S. transitionalis.

In outdoor enclosures (5.7 x …

Flight Muscle Histolysis In The Female House Cricket, Acheta Domesticus., Rush Hoyet Oliver

LSU Historical Dissertations and Theses

Flight muscle histolysis was investigated in the dorsal longitudinal muscles (DLMs) of the cricket. Histolysis in the DLMs was characterized by analysis of total protein content, tissue wet weight, and relative percent muscle shortening. Initial declines of total protein indicated the JH signal initiating histolysis occurred by Day 2. Histolysis was essentially complete by Day 3. Ligation of Day 1 crickets prevented histolysis but this inhibition could be prevented by continual topical treatments with methoprene. Ligation of Day 2 crickets did not prevent histolysis. A requirement for active protein expression was demonstrated by analysis of synthesis block by cycloheximide and …

Using The Spot-Mapping Censusing Technique To Assess Changes In Breeding Bird Communities At Santa Ana National Wildlife Refuge, Alamo, Texas, 1940-1996, Alberto Cantu

Theses and Dissertations - UTB/UTPA

Results of breeding-bird censuses done by Davis in 1940 and by Gehlbach between 1973-1978 at Santa Ana National Wildlife, Alamo Texas, were compared to a 1995-1996 bird survey done in Gehlbach's study area. According to the Wilcoxon rank-sum test, bird densities in 1940 and 1995-1996 were similar, while 1973-1978 densities were lower. The 1995-1996 bird community was 76% similar to both the earlier studies. However, the communities studied in 1940 and 1973-1978 had only a 60% similarity. Negligible differences in bird densities and species composition were found between the 1995 and 1996 communities. Differences are attributed to changes in vegetation …

Importance Of A Siderophore In The Pathogenesis And Virulence Of Photobacterium Damsela Subsp. Piscicida In Hybrid Striped Bass (Morone Saxatili X Morone Chrysops)., John Phillip Hawke

LSU Historical Dissertations and Theses

Photobacterium damsela subsp. piscicida, formerly Pasteurella piscicida, is an important new pathogen of hybrid striped bass cultured in brackish water on Louisiana mariculture farms. Louisiana isolates compared with strains of P. damsela subsp. piscicida from Greece, Japan, Israel and Chesapeake Bay, USA and were found to be identical in biochemical phenotype and enzymic activity. Small plasmids of 8 and 5 kb were unique to Louisiana strains. Sequential daily bacteriology and histopathology on hybrid striped bass experimentally infected by immersion revealed that following high doses (13,000 CFU/ml) the gills and spleen are colonized first as early as 24 hours PI, followed …

Breeding Ecology Of Songbirds In Bottomland Hardwood Forests Of Louisiana., Keith Ouchley

LSU Historical Dissertations and Theses

I examined productivity, survivorship and nest-site habitat characteristics of small terrestrial landbirds breeding in bottomland hardwood forest study sites in Louisiana. Bottomland hardwood forests are the dominate ecosystem of riverine floodplains in the southeastern United States, and these forests support a diverse bird community. Over 80 percent of this forest type has been lost, primarily due to agricultural clearing, and the relative abundance of many bird species that breed in these forests has also declined. The outcomes of 790 nests of 33 species were determined. For most species, productivity was greater in large forest tracts than in small tracts. Predation …

Life History And Reproductive Biology Of The Estuarine Nudibranch Tenellia Adspersa (Nordmann, 1845), Charles Morgan Chester

Doctoral Dissertations

Tenellia adspersa is a small (5-7 mm) estuarine nudibranch. Tenellia lives in a highly variable environment and feeds on many gymnoblastic and calyptoblastic hydroids. I undertook a field study at four sites in the Great Bay Estuary (Durham, New Hampshire) to assess the amount of variability in abiotic and biotic factors. Environmental parameters (temperature and salinity) and the availability of hydroid prey (Cordyolophora lacustris and Obelia spp.) varied within the generation time of Tenellia and could affect its life history.

Laboratory studies compared the growth rate of the hydroid, Cordylophora to the growth rate and predation rate of Tenellia. The …

Ecological Patterns During Ontogeny In The Bicolor Damselfish, Stegastes Partitus, Poey, Richard Stephen Nemeth

Doctoral Dissertations

This dissertation examined the ecological constraints during the early life history of the bicolor damselfish, Stegastes partitus Poey (Perciformes, Pomacentridae). A series of studies, conducted in Teague Bay, St. Croix and Discovery Bay, Jamaica between 1991 and 1996, determined the cause of variation in length of the planktonic larval period, the effect of larval history on settlement success and examined the causes behind the patterns of distribution and population structure seen throughout its geographic range. Variable growth rates in early-stage larvae established a canalized trajectory toward larval competence and provides a mechanism for determining planktonic duration. Using otolith microstructure I …

Foraging Behavior And Habitat Selection Of Insectivorous Migratory Songbirds At Gulf Coast Stopover Sites In Spring., Chao-Chieh Chen

LSU Historical Dissertations and Theses

Abundance of some species of Nearctic-Neotropical migrants has been declining dramatically since 1970. Most literature about Neotropical migrants is from the breeding grounds, and some is from the wintering grounds; very little is from stopover sites. I studied foraging behavior and habitat selection of insectivorous migratory songbirds at three stopover sites along northern coast of the Gulf of Mexico during spring migrations of 1993-1995. Each migrant species had its unique combination of foraging behavior and habitat use during stopover. Migrants selected certain habitat strata and plant species and avoided others. The decrease of understory vegetation in the reduced plots had …

Analysis Of Host-Parasite Cospeciation: Effects Of Spatial And Temporal Scale., James W. Demastes

LSU Historical Dissertations and Theses

All species of pocket gophers (Geomyidae) are parasitized by at least one species of chewing louse (Trichodectidae), and recent genetic studies have demonstrated that a pattern of cospeciation exists between these hosts and parasites (Hafner and Nadler, 1988; Hafner et al., 1994). Little work has been done on this host-parasite system at lower taxonomic (intrageneric) levels. Although cospeciation is evident in a study of pocket gophers within the genus Geomys and their chewing lice (Geomydoecus), reticulate evolution and retention of ancestral lineages obscure the pattern (Chapter 2). One key to understanding how these patterns of cospeciation are produced and how …

Some Physiological Effects Of Stress In The American Cockroach Periplaneta Americana (L), Shigui Liu

Digitized Theses

The effects of different forms of stress on the American cockroach, Periplaneta americana (L.) have been systematically examined. This study demonstrated that at least two stress-related events occurred in the haemolymph of the American cockroach. First, the data clearly indicated that a large increase in hypertrehalosemic hormones occurred in the haemolymph of stressed cockroaches. Secondly, proteolytic activity in the haemolymph of stressed cockroaches was greatly increased. The increase of both hypertrehalosemic hormones and proteolytic activity in the haemolymph appeared to be a non-specific response to different forms of stress, including chemical poisoning with lindane, immobilization, forced movement, starvation, and elevated …

Expression Of Sodium Pump Subunit Genes During Mouse Preimplantation Development, Daniel James Macphee

Digitized Theses

The Na,K-ATPase or sodium pump is an enzyme that is found in most animal cells. The enzyme pumps sodium and potassium ions against their concentration gradients and is hypothesized to be a mediator of fluid accumulation during mouse preimplantation development. The purpose of the present study was to determine, using reverse transcriptase-polymerase chain reaction (RT-PCR), whether all {dollar}\alpha\ (\alpha1,\ \alpha2,\ \alpha3,\ \alpha4{dollar}) and {dollar}\beta\ (\beta1{dollar} and {dollar}\beta{dollar}2) isoforms of the sodium pump were expressed during preimplantation development. Previous work by Watson and Kidder (1988) had shown that the {dollar}\alpha{dollar} subunit was localized to the basolateral domains of mural trophectoderm surrounding …

Male Reproductive Success And The Mating System Of Bushy-Tailed Woodrats, Michael Graham Topping

Digitized Theses

Bushy-tailed woodrats are nocturnal cricetid rodents distributed throughout the mountainous regions of western North America. Despite a number of studies on the population ecology of this species, little is known about the behaviour of males during the breeding season.;I investigated the reproductive behaviour of male bushy-tailed woodrats in three ways. First, I examined the spatial distribution of individuals within a breeding population, using radiotelemetry and mark-recapture livetrapping. Both males and females exhibited considerable overlap with animals of both sexes, mean intersexual and intrasexual overlap values for each sex did not differ in two of the three years of study. This …

Testing For Mate Choice And Competition In Convict Cichlids Using Ecologically Relevant Contexts, Diane Kathleen Urban

Digitized Theses

Mate choice and intrasexual competition in convict cichlids, Cichlasoma nigrofasciatum, was investigated in the laboratory, during courtship, nest building, guarding eggs, and guarding fry. During courtship, females were expected to use male body size to indicate quality and to compete for large males. Females and newly introduced males were tested under two conditions: Treatment1--the males were similar in body length; and Treatment 2--one male was larger than the other two. No significant difference was found between treatments in the frequency of female proximity to males or in the frequency of female-female aggressive behaviour. However, the large male of Treatment 2 …

Comparative Reproductive Ecology Of Female Buffleheads (Bucephala Albeola) And Barrow's Goldeneyes (Bucephala Islandica) In Central British Columbia, Jonathan Edward Thompson

Digitized Theses

Waterfowl (Anseriformes) generally have high energetic costs for reproduction because they lay large, energy-rich eggs. Consequently, many temperate nesting ducks (Anatinae) occupy seasonally productive environments to meet nutritional requirements for egg production. However, ducks in the genus Bucephala often breed in unproductive boreal and montane regions. This study was conducted to investigate nutritional aspects of reproduction in female Buffleheads (Bucephala albeola) and Barrow's Goldeneyes (Bucephala islandica) breeding in central British Columbia.;Diet composition of breeding female Buffleheads and Barrow's Goldeneyes, which consisted primarily of benthic insects, was similar, providing support for the food defense hypothesis as an explanation for evolution of …

Population Dynamics, Production And Resource Allocation In The Zebra Mussel, Dreissena Polymorpha, From The Lower Great Lakes, Canada, Margo Elizabeth Chase

Digitized Theses

Five populations of Dreissena polymorpha from three lakes (Lake St. Clair, Lake Erie and Lake Ontario) were examined to determine the population dynamics, reproductive cycle, secondary production and the allocation of resources to somatic tissue and shell, and gamete production.;Variation in life history characteristics, such as lifespan, age at first reproduction, maximum size and fecundity were observed both within and among sites, although the among-site variation was greater. The lifespan of D. polymorpha ranged from 2 to {dollar}>{dollar}4 years depending on the lake. The onset of sexual maturity was related to size, not age. Individuals became sexually mature between …

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 …

Behavioral And Morphological Development Of Immature Hawaiian Freshwater Fishes., David Chestine Tate

LSU Historical Dissertations and Theses

Studies of recent fish collections from 17 streams on four islands in Hawai'i provided key characteristics for species identification of immature forms of five native species of freshwater gobioids. Young Eleotris sandwicensis lack fused pelvic fins. A suborbital bar identifies Stenogobius hawaiiensis. Awaous guamensis can be distinguished by lack of notches in the upper lip, Lentipes concolor by a single median notch, and Sicyopterus stimpsoni by three notches. Recruitment from oceanic plankton occurred year round but peaked from February to April. Lentipes invaded streams mainly during the day with the wave surge; Sicyopterus entered mostly during the day regardless of …

Functional Anatomy Of The Integument And Subcutaneous Structures Of The Head, Neck And Thorax Of The Domestic Turkey, Meleagris Gallopavo., Kumudini Nishantha De Silva

LSU Historical Dissertations and Theses

The microdissection of the integument and subcutaneous structures of the head, neck, and thorax of the Domestic Turkey, Meleagris gallopavo, revealed a complex system with several distinct layers of connective tissue, smooth and striated musculature, and fat bodies (corpora adiposa). These layers show structural variations across the body surface, and the patterns of variation of the different layers correlate with one another. The smooth apterial muscles and the striated subcutaneous muscles complement each other in moving certain feather tracts. Fat tissue is deposited in the dermis as dermal fat, in the Fascia superficialis, and in distinct fat bodies associated with …

Daily Variations Of Lipogenic Activities In Japanese Quail (Coturnix Coturnix Japonica)., Bruce L. Tedford

LSU Historical Dissertations and Theses

Studies were made in Japanese quail (Coturnix c. japonica) to determine if daily variations of plasma insulin and de novo lipogenesis exists and examine the roles of daily variations in lipogenic responsiveness to insulin and prolactin. A daily variation in plasma insulin levels exists in quail fed ad libitum, with photophase levels 4.6 times greater than scotophase levels. This variation was not driven exclusively by the feeding of the quail, because insulin levels had dropped by dark onset, yet all bird's crops contained food at this time. There was a daily variation in the amount of $\sp{14}$C-acetate labelled lipids extracted …

A Comparison Of Ecological Factors Affecting Two Species Of Lotic Molluscs., Paul David Johnson

LSU Historical Dissertations and Theses

This study examined habitat-mediated differences in the population structure of two species of stream molluscs, the Louisiana pearl-shell mussel, Margaritifera hembeli, a protected species, and Elimia semicarinata, a pleurocerid gastropod. In 1991 I located Margaritifera hembeli in a drainage system where it was previously unknown, and describe here the distribution of M. hembeli in the Bayou Rigolette drainage in Grant Parish, Louisiana. The mussel was limited to small second- and third-order lotic systems. Of several physicochemical and habitat parameters, specific conductance, Ca$\sp{+2}$ concentration, sediment particle size, sediment compaction and channel width were most important in explaining abundance. Substratum stability was …

Bamboo Specialization In Amazonian Birds., Andrew Ward Kratter

LSU Historical Dissertations and Theses

By spot-mapping territories of lowland forest birds in southeastern Peru, 19 "bamboo specialists" were documented to be restricted to thickets of bamboo (Guadua weberbaueri). Six specialists are restricted to thickets throughout their entire geographic range (obligate bamboo users); seven specialists may use other habitats sparingly away from southeastern Peru (near-obligate bamboo users); the remaining six species are frequent users of habitats lacking bamboo in area besides southeastern Peru (facultative bamboo users). The 19 specialists, all insectivorous, were classified into five guilds based on foraging maneuver and substrate preferences: four sallying tyrannid species; four arboreal antbirds; four stem-searching specialists; four dead-leaf-searching …