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A Case Study In Amazonian Biogeography: Vocal And Dna -Sequence Variation In Hemitriccus Flycatchers., Mario Cohn-Haft
A Case Study In Amazonian Biogeography: Vocal And Dna -Sequence Variation In Hemitriccus Flycatchers., Mario Cohn-Haft
LSU Historical Dissertations and Theses
Ongoing debate about the evolutionary history of the Amazonian avifauna suffers from a shortage of data. Especially needed are thorough geographic sampling, sensitive markers of genetic diversity, and historical data in the form of explicit phylogenies. I examined patterns of geographic variation in three widespread species complexes of nearly identical Amazonian flycatchers in the genus Hemitriccus, based on spectrographic analysis of vocalizations and phylogenetic analysis of DNA sequences (1026 base pairs of cytochrome b from 44 individuals) from throughout Amazonia. Although members of the three complexes are extremely difficult to distinguish morphologically and have long been confused by taxonomists, they …
Molecular Systematics And Historical Biogeography Of The Tree Shrews (Tupaiidae)., Kwai Hin Han
Molecular Systematics And Historical Biogeography Of The Tree Shrews (Tupaiidae)., Kwai Hin Han
LSU Historical Dissertations and Theses
This dissertation examined the molecular systematics and historical biogeography of tree shrews (Tupaiidae). Comparison of cytochrome b sequences and DNA hybridization data suggests that cytochrome b sequences evolved 7.9 to 13.4 times faster than single-copy nuclear DNA. These two data sets are taxonomically congruent. They indicate that the Mindanao tupaiid Urogale everetti is a member of Tupaia, and that there is lineage-based variation in rates of evolution among the tupaiids. A new species of Tupaia from Sarawak (Malaysia), T. stuebingi, was described using morphological, ecological, and cytochrome b sequence data. This lowland species is generally similar in size to the …
Ecology Of Seagrass Fishes And Macroinvertebrates On Guatemala's Atlantic Coast., Alejandro Arrivillaga
Ecology Of Seagrass Fishes And Macroinvertebrates On Guatemala's Atlantic Coast., Alejandro Arrivillaga
LSU Historical Dissertations and Theses
The ecology of fishes and macroinvertebrates inhabiting shallow seagrass beds was studied at Bahia La Graciosa, located in Amatique Bay in the Caribbean coast of Guatemala. The study area included extensive turtle grass, Thalassia testudinum, meadows over muddy substrate, whereas a more exposed shoreline also supported turtle grass meadows over sandy substrates outside the bay. A total of 166 samples were collected across two seasons and habitat types in three sampling trips to the area with a cylindrical drop sampler. Diversity and abundance of fishes and macroinvertebrates inhabiting seagrass and adjacent bare-sand sites were described to assess the relative importance …
American Alligator Nesting Ecology In Impounded Marsh Habitat, Louisiana., Steven Richard Reagan
American Alligator Nesting Ecology In Impounded Marsh Habitat, Louisiana., Steven Richard Reagan
LSU Historical Dissertations and Theses
The goal was to monitor a large number of female alligators over a 3-year period to obtain information on alligator nesting ecology. This dissertation, although designed to estimate annual nesting rates, provides additional meaningful information on methods of capture, tag retention rates, nest spacing patterns, segregation of size classes, nest site fidelity, the relationship between attendance and nest success, the effects of fire ants on alligator nest success, the relationship between hatchling alligators and their mother, and hatchling dispersal. Passive integrated transponder (PIT), monel web, and cranial mounted reflector tags were evaluated for marking and identifying alligators. Use of harmonic …
Host And Parasite Interactions Among Three Symbionts: Pocket Gophers, Chewing Lice, And Endosymbiotic Bacteria., David Lee Reed
Host And Parasite Interactions Among Three Symbionts: Pocket Gophers, Chewing Lice, And Endosymbiotic Bacteria., David Lee Reed
LSU Historical Dissertations and Theses
This study investigates the patterns of cophylogeny documented between pocket gophers (Rodentia: Geomyidae) and their ectoparasitic chewing lice (Phthiraptera: Trichodectidae). The first two chapters investigate the mechanisms that reinforce cospeciation in this system. Chapter one examines whether mammalian hair diameter is a resource tracked by chewing lice, and thus reinforces the patterns of cospeciation. I found that hair diameter of pocket gophers is correlated with gopher body size and the body size of the ectoparasitic chewing lice. Hair diameter also is correlated with size of the rostral groove, which chewing lice use to grasp hair shafts of pocket gophers. In …
Systematics Of The Polymorphic North American Rat Snake (Elaphe Obsoleta)., Frank Thomas Burbrink
Systematics Of The Polymorphic North American Rat Snake (Elaphe Obsoleta)., Frank Thomas Burbrink
LSU Historical Dissertations and Theses
The North American rat snake (Elaphe obsoleta) complex is composed of seven uniquely colored subspecies of E. obsoleta and the sister species E. bairdi. Maximum parsimony (MP) and maximum likelihood (ML) analysis of two mitochondrial DNA genes from 73 E. obsoleta and E. bairdi, produced well-supported trees that do not conform to the currently accepted subspecies. Both ML and MP trees were significantly shorter than the trees in which each subspecies was constrained to be monophyletic. The subspecies of E. obsoleta do not represent genetic lineages. Instead, molecular evidence revealed the existence of four well-supported mtDNA clades confined to particular …
Experimental Mammalian Predator Removal And Other Factors Affecting Dabbling Duck Reproduction In North Dakota., Pamela Renee Garrettson
Experimental Mammalian Predator Removal And Other Factors Affecting Dabbling Duck Reproduction In North Dakota., Pamela Renee Garrettson
LSU Historical Dissertations and Theses
In the prairie pothole region, high predation rates often reduce duck nest success below the 15--20% thought necessary for population stability. Lethal removal of mammalian predators of duck nests is one potential management option, but there is little reliable information about the effects on nest success of removing mammalian predators without using poisons. On 16 4,150-ha blocks, half of them trapped during spring and summer, I found higher ( P < 0.001) nest success on trapped sites (45%) than on untrapped sites (17%). There were no year (P = 0.296), year-treatment (P = 0.423), or species-treatment (P > 0.895) effects. Nest success of blue-winged teal (Anas discors) and gadwalls (A. strepera) was higher than that of mallards ( A. platyrhynchos) and pintails (A. acuta, P = 0.028) on …
Effects Of Fluctuating Salinity, Nutritional State, And Temperature On Leptasterias Spp. From Little Port Walter, Alaska., Jeffrey William Tamplin
Effects Of Fluctuating Salinity, Nutritional State, And Temperature On Leptasterias Spp. From Little Port Walter, Alaska., Jeffrey William Tamplin
LSU Historical Dissertations and Theses
The effects of fluctuating salinity, nutritional state, and temperature on activity, oxygen consumption, feeding, and growth rates were analyzed on seasonally collected Leptasterias spp. (Echinodermata: Asteroidea) from Little Port Walter, AK. Leptasterias aspera and L. epichlora were collected on June 10, 1994, divided into size groups, and perivisceral fluid osmolality was measured every three hours during a 12 h 30-10-30‰S fluctuating cycle. The perivisceral fluid osmolality of larger individuals fluctuated less than that of smaller sea stars. The perivisceral fluid osmolality of small and large Leptasterias spp. closely tracks the ambient water osmolality during tidal cycles. Leptasterias spp. were collected …
Phylogeography Of Two Loligo Squid (Cephalopoda: Myopsida) In The Gulf Of Mexico And The Northwestern Atlantic Ocean., Scott William Herke
Phylogeography Of Two Loligo Squid (Cephalopoda: Myopsida) In The Gulf Of Mexico And The Northwestern Atlantic Ocean., Scott William Herke
LSU Historical Dissertations and Theses
Based on restriction fragment length polymorphisms (RFLP) in mitochondrial DNA, the population structures of two species of Loligo squid were analyzed in the context of the classic Gulf of Mexico-Atlantic Ocean phylogeographic pattern. A 709-bp fragment of the cytochrome c oxidase (subunit I) gene was amplified by PCR from 356 L. pealei and 431 L. plei. Between latitudes 25°N and 43°N, each species had three common (>5% frequency) haplotypes and many rare haplotypes. Sequence data from all haplotypes indicated that nucleotide divergence between the two species ranged from 13.7 to 15.0% (transition-transversion ratio of ∼1.5; two inferred amino acid …
Systematics, Ecology, And Social Biology Of The Musk Duck (Biziura Lobata) Of Australia., Kevin Grant Mccracken
Systematics, Ecology, And Social Biology Of The Musk Duck (Biziura Lobata) Of Australia., Kevin Grant Mccracken
LSU Historical Dissertations and Theses
Musk Ducks (Biziura lobata) exhibit a number of unusual morphological and behavioral traits. The most notable of these include: greatly abducted hind-limbs for underwater swimming efficiency, extreme sexual size dimorphism and pronounced structural dimorphism, lek display activity, elaborate sexual display repertoires, and the distinctly non-waterfowl-like trait of provisioning young with all their food from the time of hatch until fledging. Despite such peculiarities and obvious theoretical potential in the areas of comparative morphology, sexual selection, and brood ecology, few studies of Musk Ducks have been undertaken, and those to date have been either small in scope and design, or focused …
Comparative Structure And Function Of Intrinsic Gill Muscles In Freshwater Bivalve Molluscs., Scott Medler
Comparative Structure And Function Of Intrinsic Gill Muscles In Freshwater Bivalve Molluscs., Scott Medler
LSU Historical Dissertations and Theses
The lamellibranch gill is used for various vital functions ranging from food capture to ion regulation. The foundation for many of these functions is the transport of water through the gill. This dissertation examines the organization of intrinsic gill muscles and the associated connective tissue in the freshwater bivalve Dreissena polymorpha with comparisons made to Corbicula fluminea and Toxolasma texasensis. Gill muscles can be divided into two groups: those associated with the connective tissue sheets that underlie external and internal gill epithelia; and those encased in connective tissue bands oriented perpendicular to the bases of gill filaments. The sets of …
Ecology And Loss Assessment Of Selected Homopteran Pests On Sugarcane: Interactions With The Fire Ant, Solenopsis Wagneri Santschi., Andrew Evans Woolwine
Ecology And Loss Assessment Of Selected Homopteran Pests On Sugarcane: Interactions With The Fire Ant, Solenopsis Wagneri Santschi., Andrew Evans Woolwine
LSU Historical Dissertations and Theses
Field studies in 1995, 1996, and 1997, using insecticides to alter population densities of yellow sugarcane aphid, Sipha flava (Forbes), West Indian canefly, Saccharosydne saccharivora (Westwood) and the pink sugarcane mealybug, Saccharicoccus sacchari (Cockerell), indicated that sugarcane infested by these insects did not suffer sugar quality loss (as measured by brix, polarity, sucrose, purity, and theoretical recoverable sugar (TRS)). There was no apparent indication that Homoptera stressed sugarcane (indicated by concentrations of free amino acids in extracted sugarcane juice). A very slight, but significant increase in the percent brix was observed in sugarcane juice extracted from stalks washed free of …
Airbirds: Adaptative Strategies To The Aerial Lifestyle From A Life History Perspective., Manuel Marin-Aspillaga
Airbirds: Adaptative Strategies To The Aerial Lifestyle From A Life History Perspective., Manuel Marin-Aspillaga
LSU Historical Dissertations and Theses
"Airbirds" are defined as those birds that are adapted to almost constant life on the wing and do not perch, except for breeding and roosting. They use the air as the only medium in which to find and gather food. One taxon meets that definition: the swifts (Apodidae). Foraging zones of airbirds can be segregated in terms of clutch size, commuting foraging distance, nestling period, and nestling feeding rate. This study looked at foraging behavior and nestling diet, incubation patterns and mode of development in cypseloidine swifts, that as a group has extreme life history patterns. In a temperate one-egg …
The Effects Of Pah-Contaminated Sediments On Benthic-Feeding Fishes And Their Associated Prey., Candace Gay Hinkle-Conn
The Effects Of Pah-Contaminated Sediments On Benthic-Feeding Fishes And Their Associated Prey., Candace Gay Hinkle-Conn
LSU Historical Dissertations and Theses
Subtidal sediments near Port Fourchon, Louisiana, USA, have been contaminated with produced water, as indicated by the levels of polycyclic aromatic hydrocarbons (PAH) for over four decades. Studies were undertaken to examine the effect of produced water/PAH on the potential for trophic transfer (from meiofauna and small macrofauna to benthic-feeding fishes) of sediment-bound contaminants. A survey of meiofaunal communities along a putative pollution gradient from the produced water outfall to a distance of 1 km found that meiofauna densities were significantly higher at the most contaminated sites ($\sim$10,000 ng PAH g$\sp{-1}$ dry sediment). The community at the most contaminated sites, …
Early Fertilization Events In The Freshwater Zebra Mussel, Dreissena Polymorpha., Michael James Misamore
Early Fertilization Events In The Freshwater Zebra Mussel, Dreissena Polymorpha., Michael James Misamore
LSU Historical Dissertations and Theses
The morphological and functional mechanisms involved in the early fertilization events in the freshwater zebra mussel Dreissena polymorpha (Bivalvia:Veneroida:Dreissenidae) are presented. Mature adults release gametes in response to external applications of 5-hydroxytryptamine. Sperm retain a primitive morphology consisting of a head, midpiece and tail The head is approximately 1.6 $\mu$m in diameter and 4 $\mu$m in length. An acrosomal vesicle is highly compartmentalized with a central axial core containing actin. The midpiece is composed of 4 mitochondria and a pair of centrioles. A single flagellum is elaborated from the distal centriole. The eggs of D. polymorpha are 50-60 $\mu$m in …
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
Metamorphosis Of The Hawaiian Stream Goby Sicyopterus Stimpsoni: A Structural, Functional, And Behavioral Analysis., Heiko Lars Schoenfuss
LSU Historical Dissertations and Theses
The endemic goby Sicyopterus stimpsoni is unique among five species of Hawaiian freshwater fishes because it undergoes rapid metamorphosis of cranial structures during postlarval development. These fishes are amphidromous and return after a prolonged stay in the ocean to streams where they are confined to estuaries until completion of cranial restructuring. Within 48 hours after entering fresh water, head width increases significantly, while total length and head length remains unchanged. Weight decreases by approximately 15% during this period. The upper lip enlarges greatly, and the mouth position shifts from terminal to nearly ventral. Shape analysis of radiographs taken from a …
Community Structure And Habitat Preferences Of Intertidal Fishes Of The Eastern Canary Islands: Fuerteventura, Gran Canaria, And Lanzarote, With A Behavioral Description Of Mauligobius Maderensis (Osteichthyes: Gobiidae)., Richard Patrick Cody
LSU Historical Dissertations and Theses
Community structure and relative habitat preferences of intertidal fishes from the eastern Canary Islands of Fuerteventura, Gran Canaria, and Lanzarote were examined in a study of 354 tidepools at 33 localities. Habitat use and behavior of the most abundant fish Mauligobius maderensis were examined on Gran Canaria and Lanzarote. Of the 27 species encountered, 11 were common to each of the islands. The most abundant species were: M. maderensis, Parablennius parvicornis, Gobius paganellus, Coryphoblennius galerita, and Chelon labrosus. In a Two-way indicator species analysis Fuerteventura and Lanzarote localities clustered together. The same analysis differentiated between species that inhabited the upper …
Movements, Habitat Use, And Survival Of Female Northern Pintails In Southwestern Louisiana., Robert Ripley Cox Jr
Movements, Habitat Use, And Survival Of Female Northern Pintails In Southwestern Louisiana., Robert Ripley Cox Jr
LSU Historical Dissertations and Theses
I developed portable platforms for setting rocket nets in open-water habitats, and used them to capture 1116 waterfowl of 7 species during winters 1991-92 and 1992-93 in southwestern Louisiana. Distance and duration of evening flights of female northern pintails (Anas acuta; hereafter pintails) from Lacassine National Wildlife Refuge increased with date within wintering period, and generally were greater than previously reported estimates for wintering waterfowl. I found that diurnal use of refuges by females increased during hunting seasons, contradicting Tamisier's hypothesis that use of refuges by pintails in southwestern Louisiana is not influenced by hunting. Female pintails extensively used privately …
Nesting Ecology Of The White-Faced Ibis (Plegadis Chihi) In Southwestern Louisiana., Kathleen Carson Garrett
Nesting Ecology Of The White-Faced Ibis (Plegadis Chihi) In Southwestern Louisiana., Kathleen Carson Garrett
LSU Historical Dissertations and Theses
I studied the nesting ecology of the White-faced Ibis (Plegadis chihi) during the summers of 1994 and 1995 in three colonies in Lacassine National Wildlife Refuge, southwestern Louisiana. Data were collected on colony-site characteristics, chronology (with abundance) of colony formation, reproductive success, and growth and development of ibis nestlings. Small colonies nested in dense buttonbush (Cephalanthus occidentalis) and water willow (Decodon verticillatus) "islands." The largest colony nested in black willows (Salix nigra) (3.2 ha)--a habitat unique to ibis populations in Louisiana--with nests heights up to 7.5 m. Cattle egrets (Bubulcus ibis) (62%) and ibises (36%) were the most abundant species. …
Biogeographic, Ecological, And Evolutionary Aspects Of South American Austral Migration, With Special Reference To The Family Tyrannidae., Robert Terry Chesser
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 …
Effects Of Environmental Factor Gradients On Survival, Growth And Physiology Of Two Species Of Crab Within The Genus Callinectes., John Louis Guerin
Effects Of Environmental Factor Gradients On Survival, Growth And Physiology Of Two Species Of Crab Within The Genus Callinectes., John Louis Guerin
LSU Historical Dissertations and Theses
Effects of environmental factor gradients on growth, molting and physiology of crabs within the genus Callinectes were examined. Juvenile blue crabs, Callinectes sapidus, were exposed to a range of dissolved cadmium concentrations at two salinities (2.5 and 25$\perthous$). 21-day LC$\sb{50}$'s were lower at 2.5$\perthous$ (19 $\mu$g l$\sp{-1}$) than at 25$\perthous$ (186 $\mu$g l$\sp{-1}).$ Crabs were exposed to Cd levels of 0, 50 and 100 $\mu$g l$\sp{-1}$ for bioenergetic measurements. Energy expenditure did not vary with cadmium. Scope for growth, energy consumption and energy absorption were unaffected by Cd at 25$\perthous,$ but decreased with exposure to cadmium at 2.5$\perthous.$. Juvenile lesser …
The Production Of Triploid Oyster Larvae (Crassostrea Virginica (Gmelin)) In Louisiana., John Eric Supan
The Production Of Triploid Oyster Larvae (Crassostrea Virginica (Gmelin)) In Louisiana., John Eric Supan
LSU Historical Dissertations and Theses
Gonadal recycling of oyster broodstock, salinity effects during induction, and cytochalasin B (CB) dosage were investigated as factors affecting the production of triploid oyster larvae in Louisiana. These factors were studied at an oyster hatchery on Grand Isle, LA during 1992-1994 to help transfer triploid oyster technology to the Gulf region. Oyster broodstock were held nearshore in Caminada Bay, Louisiana and histologically analyzed between induced spawnings and during the winter of 1992-1993. Gametogenesis was analyzed qualitatively by developmental staging and quantitatively using mean gonad/body ratios (GBR) per section. The monthly percent occurrence of the developmental stages, as well as histological …
Behavioral And Chemical Ecology Of Formosan Subterranean Termites, Coptotermes Formosanus Shiraki., Jian Chen
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 …
The Role Of Infaunal And Epifaunal Suspension Feeding Macrofauna On Rates Of Benthic-Pelagic Coupling In A Southeastern Estuary., Christine Miller-Way
The Role Of Infaunal And Epifaunal Suspension Feeding Macrofauna On Rates Of Benthic-Pelagic Coupling In A Southeastern Estuary., Christine Miller-Way
LSU Historical Dissertations and Theses
This research investigated the effects of two suspension feeding bivalves, the infaunal Rangia cuneata, and the epifaunal Crassostrea virginica, on benthic-pelagic coupling in Fourleague Bay, LA, a river-dominated estuary. A continuous-flow microcosm system was developed to overcome recognized limitations of batch methodology and to facilitate manipulations designed to investigate the ecological role of benthic macrofauna. Experiments comparing traditional batch methodology to continuous-flow methodology indicated that rates of benthic processes were consistently greater when measured using continuous-flow methodology. Examinations of concentrations indicated that differences were due to concentration gradients which departed from ambient over time in the batch cores. Over an …
Studies On The Energy Mobilizing Hormones In Insects., Subrata Das
Studies On The Energy Mobilizing Hormones In Insects., Subrata Das
LSU Historical Dissertations and Theses
Chemical factors controlling the energy mobilization in three species of insects were identified, partially characterized and their role in the process of energy mobilization were studied. High performance liquid chromatographic fractions were isolated from methanolic extracts of the corpora cardiaca (CC) from the honeybee Apis mellifera, the paper wasp Polistes exclamans and the house cricket Acheta domesticus. Each species had a single active fraction that was able to elevate the lipid titer in Acheta. Pyroglutamate aminopeptidase digestion of isolated active fractions indicated that these molecules are all peptides with a terminal pyroglutamate. Methanolic extracts of CC from Apis, Polistes and …
Physiological And Biochemical Responses To Hypoxia In The Blue Crab, Callinectes Sapidus Rathbun, The Lesser Blue Crab, Callinectes Similis Williams, And The Southern Oyster Drill, Stramonita Haemastoma Linnaeus., Tapash Das
LSU Historical Dissertations and Theses
This study measured the physiological and biochemical changes associated with exposure of the juvenile blue crab, Callinectes sapidus Rathbun and the lesser blue crab. C. similis Williams, to long term (28 d) hypoxia, short term (10 d) transfer from hypoxia to normoxia and a diurnally fluctuating oxygen regime for 28 days. The southern oyster drill, Stramonita haemastoma Linnaeus, was also exposed to 28 days of constant hypoxia to compare the responses of a tolerant species with the two species of Callinectes. The 28 day LC$\sb{50}$ estimates for C. sapidus, C. similis and S. haemastoma were respectively 106, 43 and 11.5 …
Functional Morphology Of The Lingual Apparatus Of Sandgrouse (Aves: Pteroclidae)., Werner Muller
Functional Morphology Of The Lingual Apparatus Of Sandgrouse (Aves: Pteroclidae)., Werner Muller
LSU Historical Dissertations and Theses
The morphology of the lingual apparatus of three species of sandgrouse (Aves; Pteroclidae) has been described. All biomechanically important parts were included in the description, i.e., all muscles potentially involved in the functioning of the lingual apparatus, all skeletal parts, the salivary glands associated with the lingual apparatus, and the surface morphology of the oropharyngeal cavity. For each muscle its potential functions have been described. In a comparison with data from the literature of three other groups of birds it was found that the functional organization of the lingual apparatus of the sandgrouse is strikingly similar to the one found …
The Genetic Effects Of Forest Fragmentation On Amazonian Forest Birds., John Marshall Bates
The Genetic Effects Of Forest Fragmentation On Amazonian Forest Birds., John Marshall Bates
LSU Historical Dissertations and Theses
I present allozyme and mitochondrial DNA (mtDNA) data on the genetic structure of five species of Amazonian forest birds at two geographic scales. The five species, Glyphorynchus spirurus (family Dendrocolaptidae), Leptopogon amaurocephalus (Tyrannidae), Hypocnemis cantator, Myrmeciza hemimelaena, and Hylophylax poecilinota (all three Formicariidae), are common forest understory inhabitants throughout much of Amazonia. At the local geographic scale, I hypothesized that forest fragmentation affected genetic structure in these species. Study sites were in the Department of Santa Cruz, Bolivia. Six sites separated by 150 km or less for each species were sampled: three sites in continuous Amazonian forest, and three in …
Behavioral Influences On Predator-Prey Interactions Between Juvenile Teleosts And Meiofauna., John Nathan Mccall
Behavioral Influences On Predator-Prey Interactions Between Juvenile Teleosts And Meiofauna., John Nathan Mccall
LSU Historical Dissertations and Theses
Predator-prey relationships between post-larval and juvenile teleosts are greatly influenced by the manner in which feeding behavior of fish interacts with the behavior of meiofaunal prey. Juvenile starry flounder (Platichthys stellatus Pallas) in a southeastern Alaskan bay fed disproportionately on the harpacticoid copepod Microarthridion littorale (Poppe), particularly on males. This apparent selectivity was not due to differing vertical distribution of harpacticoid species or to feeding in other locations. Comparison of ingested prey to harpacticoid assemblages collected by various techniques (including near-bottom collections) suggested that the prey selection shown by starry flounder may be the result of emergent behavior of its …
Seasonal And Daily Variations In Plasma Hormone Concentrations Of The Gulf Killifish, Fundulus Grandis., Arnil Cabading Emata
Seasonal And Daily Variations In Plasma Hormone Concentrations Of The Gulf Killifish, Fundulus Grandis., Arnil Cabading Emata
LSU Historical Dissertations and Theses
Circadian rhythms of hormone secretion and responsiveness to hormones were examined in the gulf killifish. The findings provide additional information to support the hypothesis that reproductive, metabolic and behavioral activities are regulated in part by a temporal interaction of circadian rhythms. These findings include: (1) Daily injections of drugs that influence serotonergic (5-hydroxytryptophan, 5-HTP) and dopaminergic (dihydroxyphenylalanine, DOPA) activities induce conditions appropriate to either summer or winter, and can determine the manner in which a fish reacts reproductively and metabolically to water temperature, the main environmental determinant. (2) Tryptophan-enriched diets stimulated increases in plasma triiodothyronine and somatomedin-C levels, dramatically stimulated …