Browsing by Subject "bats"
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Item Molecular systematics of bonneted bats (Molossidae: Eumops) based on mitochondrial and nuclear DNA sequences(2012-05-12) Bartlett, Sarah; Bartlett,Sarah Nichole; Ammerman, Loren K.; Maxwell, Terry; Strenth, Ned; Pierce, Jason; Angelo State University. Department of Biology.Previous understanding of the relationships among the species of bats in the genus Eumops has been based on phenetic and cladistic analyses of morphological data. The objective of this study was to construct a phylogeny of the bats within the genus Eumops using DNA sequence data from 2 mitochondrial genes (cytochrome b and nicotinamide adenine dinucleotide dehydrogenase subunit 1) and 1 nuclear locus (β-fibrinogen intron 7) for members of Eumops and outgroups from the family Molossidae. Data for each locus were analyzed separately using maximum-likelihood and Bayesian methods then were combined for complete data analyses using Bayesian Inference and Bayesian concordance analysis on a total of 2715 base pairs. Our results conflicted with some of the relationships proposed in previous morphological studies. Minor disagreements existed between the individual mitochondrial and nuclear data sets. However, the monophyly of the genus was significantly supported in all of the analyses.Item Neurobiology of Bat Vocal Behavior(2012-02-14) Schwartz, Christine PatriceVocal plasticity is presumed to be a key element underlying the evolution of human speech and language, but the mechanisms and neuroanatomical basis for this plasticity remain largely unknown. The Mexican free-tailed bat, Tadarida brasiliensis, presents a unique opportunity to advance our understanding of the evolution and neurobiology of mammalian vocal communication because this animal displays elements of vocal complexity and plasticity that are more sophisticated than any mammal other than humans, including non-human primates. Current models of vocal control in mammals do not account for the vocal complexity of free-tailed bats. The purpose of this dissertation is to fill that gap in knowledge by identifying a possible neuronal basis for vocal complexity in free-tailed bats. This will be achieved by 1) providing a detailed analysis of the free-tailed bat?s vocal behaviors, 2) mapping the distribution of neurotransmitter receptor types suspected of involvement in vocal control, 3) identifying brain regions that exhibit increased neuronal activity during vocalizing, and 4) pharmacologically manipulating putative vocal control regions to confirm and characterize their function in vocalizing. Analysis of Tadarida?s vocal behavior indicated that they have a vast vocal repertoire, including many different call types, context-dependent sensory-feedback driven vocal plasticity, and syntactically-organized stereotyped songs. Their vocal behavior changed seasonally, so I mapped the distribution of melatonin binding sites in the brain, finding high densities in the striatum, similar to dopamine receptor distribution. I then used immunohistochemical labeling of the immediate early gene cfos to map neuronal activation in brains of highly vocal bats to find ROIs activated by vocal production. This technique not only identified all previously known regions of the mammalian vocal motor pathway but also revealed activity in novel brain regions that could potentially account for vocal plasticity, including a localized region of the basal ganglia, the dorsolateral caudate nucleus, and the anterior cingulate region of the frontal cortex. Pharmacological excitation of these regions evoked complex vocal sequences similar to the songs recorded in the field and lab. These results support the hypothesis that the mammalian basal ganglia may play a crucial role in the plasticity and complexity of mammalian vocal behaviors.