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Louisiana State University

Theses/Dissertations

1996

Zoology

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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 Jan 1996

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 Jan 1996

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 …


Foraging Behavior And Habitat Selection Of Insectivorous Migratory Songbirds At Gulf Coast Stopover Sites In Spring., Chao-Chieh Chen Jan 1996

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 Jan 1996

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 …