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Full-Text Articles in Ecology and Evolutionary Biology

Divergence Of Vertebrate And Insect Specific Toxin Genes Between Three Species Of Widow Spider, Shannon G. Kahn May 2015

Divergence Of Vertebrate And Insect Specific Toxin Genes Between Three Species Of Widow Spider, Shannon G. Kahn

Honors College Theses

The Brown widow spider, Latrodectus geometricus, is an introduced species to the southern United States (Brown 2008). The Brown widow is a member of the widow spider genus Latrodectus which includes the southern Black widow (L. mactans) and 29 other venomous species. All species of widow spiders produce venom which is used against both predator and prey. These venoms are composed of several different species-specific toxins, each encoded by a different gene (Graudins 2012). Previous research has shown that positive selection pressures affect the venom of snakes and snails, thus aiding in adaptive potential of the species …


Parasite Infection Mediates Trait Tradeoffs In Fundulus Heteroclitus, Sarah Dunn May 2015

Parasite Infection Mediates Trait Tradeoffs In Fundulus Heteroclitus, Sarah Dunn

Honors College Theses

To be successful, an animal must eat, grow, and reproduce. With limited resources, there are tradeoffs between these critical life history parameters but the direction of the tradeoffs is largely unknown in a changing environment. To determine whether environmental context affects life-history tradeoffs, I surveyed and quantified investment into reproduction, growth, and a proxy for immunity (parasitism), in the mummichog, Fundulus heteroclitus, a common inhabitant of salt marshes in Georgia. Three salt marsh sites along coastal Georgia (Shellman Bluff, Skidaway Island, and Tybee Island) were selected using a proxy for anthropogenic disturbance (impervious surface), which also fell along a …


Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims Jan 2015

Nonstructural Carbohydrate Concentrations Of Pine Trees As A Function Of Evolutionary History, Joshua T. Mims

Electronic Theses and Dissertations

Nonstructural carbohydrates (NSC) can supply substrate during periods when current photosynthate is unavailable or inadequate to meet metabolic demands. I hypothesized that natural selection has favored higher nonstructural carbohydrate concentrations ([NSC]) in species that have an evolutionary history of frequent disturbance and tested this using three southern pine species that have evolved under a continuum of disturbance frequencies (evolutionary history of fire ~ longleaf > slash > loblolly). Stem and root samples were collected from 12 similar-sized individual trees of each species during time periods that reflect the annual minimum and maximum [NSC]. A modified colorimetric method was performed on the samples …


Helping To Resolve Taxonomic Conflicts Within The Genus Amblyomma (Acari:Ixodidae) From A Molecular Perspective, Paula Lado Jan 2015

Helping To Resolve Taxonomic Conflicts Within The Genus Amblyomma (Acari:Ixodidae) From A Molecular Perspective, Paula Lado

Electronic Theses and Dissertations

This work sought to reassess the taxonomic status of Amblyomma parvum Aragao, 1908 and of the A. maculatum group of ticks Camicas, 1998. By using different molecular markers, 12SrDNA, 16SrDNA, DL, COI, COII (mitochondrial) and ITS2 (nuclear), I analyzed the systematic relationships between these taxa and their closest relatives. Phylogenetic analyses by maximum parsimony, maximum likelihood, and Bayesian analysis were performed in order to determine relationships among species and populations, and to determine the evolutionary history of these ixodids. The data obtained supported the hypothesis of cryptic speciation occurring within A. parvum, with the northern populations of Central America being …


Predators And Anti-Predator Behavior Of Wilson's Plover (Charadrius Wilsonia) On Cumberland Island, Georgia, Mary K. Strickland Jan 2015

Predators And Anti-Predator Behavior Of Wilson's Plover (Charadrius Wilsonia) On Cumberland Island, Georgia, Mary K. Strickland

Electronic Theses and Dissertations

Predation, the major cause of nest failure in birds, is an important factor when considering management and conservation plans. The predator assemblage in an ecosystem changes each year and can cause profound differences in bird nest survival rates. Shorebirds such as Wilson’s Plovers (Charadrius wilsonia) are ideal study species because they are declining and predator control is often a recommended component of management plans. Therefore the objectives of my research were to determine the predator assemblage of the southern end of the beach on Cumberland Island National Seashore, Georgia, and to determine how three variables affected the display …